This is from the latest CBO report. Thought you all might find this interesting.
“The composition of income for the 1 percent of the population with the highest income changed significantly from 1979 to 2007, as the shares from labor and business income increased and the share of income represented by capital income decreased. That pattern is consistent with a longer-term trend: Over the entire 20th century, labor income has become a larger share of income for high-income taxpayers, while capital income has declined as a share of their income.”