Taxes: A Brief Visual History of U.S. Taxes

Observation 3: The Rising Share of Employment Taxes. While marginal tax rates on earned income have fallen over the last three decades, employment taxes on wages split between employer and employee have only gone up. As a result, employment taxes now account for 40 percent of total federal revenue -- basically the same as individual income taxes. Revenue from corporate income, on the other hand, has fallen from more than 30 percent in 1950 to about 7 percent in 2010.

Other good graphs are at A Brief Visual History of U.S. Taxes by Derek Thompson, January 11, 2011 at The Atlantic.