After-tax income for the highest-income households grew more than it did for any other group. (After-tax income is income after federal taxes have been deducted and government transfers—which are payments to people through such programs as Social Security and Unemployment Insurance—have been added.)
CBO finds that, between 1979 and 2007, income grew by:
The share of income going to higher-income households rose, while the share going to lower-income households fell.
Shifts in the distribution of market income underlie most of the changes in the distribution of after-tax income. (Market income—or income before taxes and transfers—includes labor income, business income, capital income, capital gains, and income from other sources such as pensions.)
Government transfers and federal taxes both help to even out the income distribution. Transfers boost income the most for lower-income households, while taxes claim a larger share of income as people's income rises.
In 2007, federal taxes and transfers reduced the dispersion of income by 20 percent, but that equalizing effect was larger in 1979.