Income Distribution and Poverty (???????)

1
Income Distributionand Poverty(???????)
Chapter 15
2
(?)The Utility Possibilities Frontier(??????)

• ????????????,???????????,????????,?????,??A??????,
  ??B??????????

3
(?)The Utility Possibilities Frontier (??????)

• ??????????????,?????????A??,I?J?????????????????
• B????A?????
• B??C??????,????????????????

4
(?)The Sources of Household Income(?????????)

• Households derive their incomes from three basic
  sources
  (????????????????)
• from wages or salaries received in exchange for
  labor(??)
• from propertythat is, capital, land, and so
  forth(??) and
• from government.(?????)

5
Wages and Salaries

• ?2000??,???60????????????
• ?1999??,??????76????????????

?????????????????????,1999 ?????????????????????,1999 ?????????????????????,1999 ?????????????????????,1999 ?????????????????????,1999 ?????????????????????,1999 ?????????????????????,1999 ?????????????????????,1999
??? ??? ??? ???
?????? 10.739475? 1.454.268? 782.108?
8.503.099?
1.??????
N.T374.277 N.T543.442 N.T410.611
N.T342.004 (????,?????????)
(76) (78)
(75) (75)
2.?????
N.T107.635 N.T102.136 N.T118.110
N.T107.612 (??????,?????????????)

3.??????
N.T37.569 N.T74.197 N.T51.773
N.T29.998 (?????,????,???????)

4.????
N.T26.994 N.T27.040 N.T35.457
N.T23.882 (???????????)
???????(123-4) N.T492.487
N.T692.735 N.T545.036
N.T453.406
?????????????(2001)88?????????,http//www.dgbas.g
ov.tw/
6
Wages and Salaries

• ????????????
• ????????????
• ?????????

7
??1???????

• ??????????????????(perfectly competition
  market),??????????,???????(factors of
  production)??????????????(marginal revenue
  product),?????????????????(economic profit 0)?
• ????????,???????????(K)????(L),?m???????,w????
  ???(???????),Q????,p???????,?economic profit
  0?
• TR-TC0 gt pQ-mK-wL0 gt
  pQmKwL

8

• Taking partial derivatives, we get
• ??????????????????,???????????????????????????
  ????????????????????

9
??2??the rewards of a skill ??

• Human capital(????)
• ??????????????????????,????????????????
• ???Mens professional basketball is extremely
  popular,thus,the top NBA players make millions of
  dollars per year,?Womens professional basketball
  is less popular,thus,these womens skill go
  comparatively unrewarded,???tennis?,?Mens and
  womens ?????????,???????????????
• Rare skills can make enormous salaries
• ??Luciano Pavarotti ?????????voice,??????????
  ??????Tapes and CDs???

10
??3Differences in working conditions

• ?????????(compensating differentials)???????,?
  ?????????,???,???????,???????????
• ???publishing and television ?????,tend to be
  low-paying,??????????,??????????????,?????????????
  ???????(??????),??????????????,????????????,??????
  Human capital,???????????,??????????????,?????????
  ??

11

• ??4?multiple Household income?????????????????????
  ?????,???????????????????,??????,?????????,???????
  
• ??5?minimum wage(????)?????????????,??????????????
  ???,?????????????????????????minimum
  wage?????????????????,???????,???????????,????????
  ,???????,?????????????????

12
??6?Unemployment(??)People earn wages only when
they have jobs.
unemployment in U.S.A
unemployment in R.O.C
Rate
Rate
5.3
11
2.7
2.6
9
1.8
1.5
1.5
3.9
1975
1982
2000
1992
2001
2000
1994
1996
1998
year
year
?????????????,2002
13
Income from Property(???????)

• Property income is income derived from ownership
  of real property and financial holdings. It
  takes the form of profits, interest, dividends,
  and rents. (???????????????,??????????,
  ???????,???????????????,???????,?????,?????,?????
  ?????????)
• The amount of property income that a household
  earns depends on
• how much property it owns, and
• what kinds of assets it owns.

14
Income from Government(?????????)

• Transfer payments are payments by the government
  to people who do not supply goods or services in
  exchange. (?????????????????????????????????????
  ?????????)
• Transfer programs are part of the governments
  attempts to offset some of the problems of
  inequality and poverty.(??????????,???????????????
  ???????)

15
Income from the government

• ???2000???,??????16????????????
• ?????1999???,??20????,???????????????16.7???20
  ????,???????????????1.9?
• Not all transfer income goes to the poor
• ?U.S.A,????????????????Social Security??
  (??????)??R.O.C,???????????????
  (?????????????????????????????????1996?????????,??
  ???????)

16
The Distribution of Income(?????)

• Economic income is the amount of money a
  household can spend during a given period without
  increasing or decreasing its net assets.
  (?????????????????????,?????????,???????)
• Wages, salaries, dividends, interest income,
  transfer payments, rents, and so forth are
  sources of economic income.(????????????????,?????
  ???????,??????,??????????)

17
Economic Income Inequality in the United States
(??????????????)
Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????) Distribution of Total Income and Components in the United States, 1997 (Percentages)(????????????????)
HOUSEHOLDS TOTAL INCOME TOTAL INCOME WAGES AND SALARIES WAGES AND SALARIES PROPERTY INCOME PROPERTY INCOME TRANSFER INCOME TRANSFER INCOME
Bottom fifth 6.0 5.7 1.0 27.6
Second fifth 9.1 11.9 4.0 26.1
Third fifth 14.7 19.9 8.4 18.7
Fourth fifth 23.6 27.3 16.4 13.9
Top fifth 46.6 35.2 70.2 13.7

Top 1 percent 10.0 3.2 29.7 1.5
Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates. Source Brookings Merge File and authors estimates.
18
?????????(disposable personal income)???,1999
????(?????)
????????()
????????(Disposable personal income)?????????????
?????(?????????)? ???????????????????(2001),????
?????????(???)?
1 (?????)
7.1
2
12.9
3
17.5
4
23.2
5
39.2
(?????)
19
Money Income(????)

• Money income is a measure of the income used by
  the Census Bureau. Because it excludes noncash
  transfer payments and capital gains income, it is
  less inclusive than economic income.(??????????
  ???????????,???????????????????,????????????????Ec
  onomic income,Money income???????????)

20
Changes in the Distribution of Income(???????????
)
Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages) Distribution of Money Income of U.S. Families by Quintiles, 1947 1997 (Percentages)
1947 1947 1960 1960 1972 1972 1980 1980 1984 1984 1994 1994 1997 1997
Bottom fifth 5.0 4.8 5.4 5.2 4.7 4.2 4.2
Second fifth 11.8 12.2 11.9 11.5 11.0 10.0 9.9
Third fifth 17.0 17.8 17.5 17.5 17.0 15.7 15.7
Fourth fifth 23.1 24.0 23.9 24.3 24.4 23.3 23.0
Top fifth 43.0 41.3 41.4 41.5 42.9 46.9 47.2

Top 5 percent 17.2 15.9 15.9 15.3 16.0 20.1 20.7
Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division. Source Statistical Abstract of the United States, various editions Department of Commerce, HHES Division.
21
The Lorenz Curve(?????)

• The Lorenz curve is a widely used graph of the
  distribution of income, with cumulative
  percentage of families plotted along the
  horizontal axis and cumulative percentage of
  income plotted along the vertical axis.

22
The Lorenz Curve for U.S.A,1997
(?????)
Figure 15.2
??????1997???????

• If income is equally distributed, there is no
  shaded area.

• More unequal distributions of income produce
  Lorenz Curves that are farther from the 45-degree
  line.

23
The Gini Coefficient(????)
The shaded area

• ?????,????????????????,???????1?,?????????????,???
  ????????,????????0?,?????????????,??????????

B
24
???????????????????????????????????????????????
Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages) Distribution of Money Income of Households, 1997 (Percentages)
ALLHOUSEHOLDS ALLHOUSEHOLDS ALLHOUSEHOLDS AFRICAN-AMERICANHOUSEHOLDS AFRICAN-AMERICANHOUSEHOLDS WHITEHOUSEHOLDS WHITEHOUSEHOLDS HISPANICHOUSEHOLDS HISPANICHOUSEHOLDS ONE-PERSONHOUSEHOLDS ONE-PERSONHOUSEHOLDS
0-10,000 11.0 21.4 9.5 16.8 25.4
10-15,000 8.1 10.5 7.8 10.7 15.8
15-25,000 14.9 17.9 14.6 19.7 20.7
25-35,000 13.3 14.2 13.2 15.0 14.0
35-50,000 16.3 14.9 16.5 16.6 11.6
50-75,000 18.1 13.1 18.8 12.2 7.7
75,000 18.4 7.9 19.7 9.1 4.7

Total 100.0 100.0 100.0 100.0 100.0
Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744. Note Totals may not add to 100 due to rounding.Source Statistical Abstract of the United States, 1999, Tables 742 and 744.
25
Poverty(??)

• In simplest terms,poverty is the condition of
  people who have very low income.
• The official poverty line(???????)????????????????
  ?????????????????????
• U.S ?official poverty line
  
• the cost of minimum food budget 3
• ???1960????,?????????poor families
  ???1/3???????????,????poverty line ???????????3?

26
Poverty in the United StatesSince 1960
Table 15.4
Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997 Percentage of Persons in Poverty by Demographic Group, 1964 - 1997
OFFICIALMEASURE1964 OFFICIALMEASURE1964 OFFICIALMEASURE1997 OFFICIALMEASURE1997 ADJUSTED FORIN-KIND TRANSFERSAT MARKET VALUE, 1997a ADJUSTED FORIN-KIND TRANSFERSAT MARKET VALUE, 1997a ADJUSTED FORIN-KIND TRANSFERSAT MARKET VALUE, 1997a
All 19.0 13.3 10.0 10.0
White 14.9 11.0 8.4 8.4
African-American 49.6 26.5 19.3 19.3
Hispanic NA 27.1 19.6 19.6
Female householder no husband present 45.9 35.1 NA
Elderly (65) 28.5 10.5 NA
Children under 18 20.7 19.9 NA
aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770. aIncludes food, housing, and medical benefits.Source Statistical Abstract of the United States, 1999, Tables 760, 763, 766, and 770.
?in-kind transfer(????????)?????,
???????????????,???????
27
The Distribution of Wealth(?????)

• The distribution of wealth is much more unequal
  than the distribution of income. Wealth is
  passed from generation to generation and
  accumulates.
• Some argue that unequal distribution of wealth is
  a natural consequence of risk taking (????) in a
  market economy.

28
The Distribution of Wealth (?????)
Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????) Percentage of Different Assets Owned by Households, 1998 Survey of Consumer Finances(??????????????)
PERCENTAGE OF OWNERS COMMON STOCK EXCLUDING PENSIONS COMMON STOCK EXCLUDING PENSIONS ALL COMMON STOCK ALL COMMON STOCK NONEQUITY FINANCIAL ASSETS HOUSING EQUITY NET WORTH
Top .5 percent 41.4 37.0 24.2 10.2 25.6
Top 1 percent 53.2 47.7 32.0 14.8 34.0
Top 10 percent 91.2 86.2 72.2 50.7 68.9
Bottom 80 percent 1.7 4.1 14.0 29.3 18.5
Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000. Source James Poterba, Stock Market Wealth and Consumption, Journal of Economic Perspectives, 14(2), 99 118 , Spring 2000.
29
The Redistribution Debate(?????????)

• Philosophical arguments against
  redistribution(???????????)
• The market, when left to operate on its own, is
  fair. One is entitled to the fruits of ones
  efforts.(????????,???????????,???????????????????
  ?,???????)
• Taxation of income for redistribution purposes is
  against freedom of contract and the protection
  of property rights.(???????????,?????????????,????
  ?????????????????,??????????????????????????)

30
The Redistribution Debate(?????????)

• Practical arguments against redistribution
  (?????????????)

• Taxation and transfer programs interfere with the
  incentives to work, save, and invest(??).
• Bureaucratic waste and inefficiency is inevitable
  in the administration of social
  programs(???????,??????,????????????????). For
  example, Professors Edgar K. Browning and William
  R. John (1984) estimated the cost of
  redistribution. They concluded that about 71 of
  income is lost in redistributing it.

31
The Redistribution Debate

• Arguments in favor of redistribution
  (???????????????)

1.A wealthy country has the moral obligation
to provide all its members with the necessities
of life. The Constitution does carry a guarantee
of the right to life. ???????,????????,?????
?????????????????????????
32
Arguments in favor of redistribution

• 2.Utilitarian justice is the idea that a dollar
  in the hand of a rich person is worth less than a
  dollar in the hand of a poor person. If the
  marginal utility of income declines with income,
  transferring income from the rich to the poor
  will increase total utility.
• ( ??????????????,?????????????????,??????1,????
  ?????????????1????????????,?????1?????,?????????
  ??(???)?)

33
??Diminishing Marginal Utility of Income
Utility
U poor
U
U rich
0
2
3
1
Income
Q rich
Q poor
34
Arguments in favor of redistribution

• 3. Rawlsian justice is a theory of distributional
  justice that concludes that the social contract
  emerging from the original position would call
  for an income distribution that would maximize
  the well-being of the worst-off member of
  society.(Rawls???John Rawls(1997)??,?????????,???
  ??????????,?????????????(social
  contract)??????????????????original
  position?state of nature,????????????,?????????
  ????????Rawls??,?????,???????????????,????????????
  ??,??????risk averse(?????),???????????????,????
  ??????????,????????????????,???????????,??,???????
  ????????,?????????????,???????????)

35
The Works of Karl Marx(????????)

• Marx did not write very much about socialism or
  communism.
• He wrote a critique of capitalism, but was not
  very clear about what would replace
  it.(??????????????,??????????????????????)
• In one essay he wrote, from each according to
  his ability, to each according to his
  needs.(???????,???????????????????,??????)

36
The Works of Karl Marx

• The labor theory of value, stated most simply, is
  the theory that the value of a commodity depends
  only on the amount of labor required to produce
  it.(???????????-??.??(1723-1970)???.???(1772-1823
  )???,?????(1818-1883)??????????,?????,????????????
  ???????????????,????)
• The owners of capital are able to extract
  surplus value out of labor.(????????????????????
  ??????????,???????????????????????,?surplus
  value?)
• ??,?????????????????????????????????

37
Effective Rates of Federal, State, and Local Taxes, 2000 (Taxes as a Percentage of Total Income) Effective Rates of Federal, State, and Local Taxes, 2000 (Taxes as a Percentage of Total Income) Effective Rates of Federal, State, and Local Taxes, 2000 (Taxes as a Percentage of Total Income) Effective Rates of Federal, State, and Local Taxes, 2000 (Taxes as a Percentage of Total Income) Effective Rates of Federal, State, and Local Taxes, 2000 (Taxes as a Percentage of Total Income)
Bottom 20 34.0
Second 20 31.2
Third 20 32.3
Fourth 20 32.6
Top 20 33.9
Top 10 34.5
Top 5 34.9
Top 1 37.0
??Effective tax rate(??????????)??????????????,??? ????????????? Source Authors estimate. ??Effective tax rate(??????????)??????????????,??? ????????????? Source Authors estimate.
38
Expenditure Programs to eliminate poverty

• (1) The Social Security system( ??????)
• is a federal system of social insurance
  programs. It includes three separate programs
  that are financed through separate trust funds
• the Old Age and Survivors Insurance (OASI)
  program (???????62?????????,???????????1999??,????
  ???12.4)
• the Disability Insurance (DI) program
  (??????????????????)
• the Health Insurance (HI, or Medicare) program
  (?65?????????????,?1998??,???????2.9).

39
Expenditure Programs to eliminate poverty

• (2) Public assistance or welfare
• consists of government transfer programs
  that provide cash benefits to
• families with dependent children whose incomes
  and assets fall below a very low level, and
• the very poor, regardless of whether or not they
  have children.

40
Expenditure Programs to eliminate poverty

• (3) The Supplemental Security Income (SSI)
  program (???????????)
• is designed to take care of the elderly who
  end up very poor.

41
Expenditure Programs to eliminate poverty

• (4) Unemployment compensation (?????)
• ???????????????,??????
• 1996???????????

Japan USA Germany France UK ROC
Unemp. Rate 3.4 5.4 11.5 12.3 7.6 2.9
Payment/Previous wage 60-80 37 60 57.4-75 80 60
Period of payment 90-300 days About 5-6 months 15-52 weeks --- --- 6 months
42
Expenditure Programs to eliminate poverty

• (5) Medicaid and Medicare are in-kind government
  transfer programs that provide health and
  hospitalization benefits
• Medicare to the aged and their survivors and to
  certain of the disabled, regardless of income,
  and Medicaid to people with low incomes.

43
Expenditure Programs to eliminate poverty

• (6) Food stamps are vouchers that have a face
  value greater than their cost and that can be
  used to purchase food at grocery stores.
• (7) Housing programs are designed to improve the
  quality of life for low-income people.
• (8)The Earned Income Tax Credit is an important
  program that allows lower income families with
  children a credit equal to a percentage of all
  wage and salary income against their income taxes.