Captain Crab sent us an article by David Johnston in the Willamette Week that looks at changes in income inequality in the U.S. since 1950.Based on an analysis of research by Saez and Piketty (2007, with updated 2008 data available at Saez’s website–the first entry under “Income and Wealth Inequality”), Johnston calculated changes in income for various income percentiles in the U.S. Between 1950 and 1980, the bottom 90% of income earners saw their incomes increase by 75% (a gain of $13,222), a rate higher than or comparable to the highest income groups. However, between 1980 and 2008, incomes of the bottom 90% has largely stagnated, while the incomes of the super rich have soared (all data in constant 2008 dollars, adjusted for inflation):

As a result the difference between the median wage and the mean wage has widened (data from the Social Security Medicare Database):

Johnston also includes data on changes in corporate income tax rates, based on IRS data. The actual tax rate — how much corporations pay after various loopholes and tax breaks — fell between 2000 and 2008:

On a similar topic, Deeb K. sent in a link to images at Think Progress showing the actual tax rate of the 400 richest Americans between 1995 and 2007, based on IRS data. During that period, the effective tax rate of this group fell by 13 percentage points:

Their incomes, on the other hand, jumped significantly:

Also see my recent post on various illustrations of inequality in the U.S.