Income Gaps Hit Record Levels In 2006, New Data Show Rich-Poor Gap Tripled Between 1979 and 2006 By Arloc Sherman
"New data from the Congressional Budget Office (CBO) show that in 2006, the top 1 percent of households had a larger share of the nation’s after-tax income, and the middle and bottom fifths of households had smaller shares, than in any year since 1979, the first year the CBO data cover. As a result, the gaps in after-tax incomes between households in the top 1 percent and those in the middle and bottom fifths were the widest on record."
http://www.cbpp.org/cms/index.cfm?fa=view&id=2789
http://www.cbpp.org/files/4-17-09inc.pdf (6pp.)