After-tax income for the top 1 percent of U.S. households almost tripled, up 275 percent, from 1979 to 2007, the Congressional Budget Office found. For people in the middle of the economic scale, after-tax income grew by just 40 percent. Those at the bottom experienced an 18 percent increase.
"The distribution of after-tax income in the United States was substantially more unequal in 2007 than in 1979," CBO Director Doug Elmendorf said in a blog post. "The share of income accruing to higher-income households increased, whereas the share accruing to other households declined."
The report, based on IRS and Census Bureau data, comes as the Occupy Wall Street movement protests corporate bailouts and the gap between the haves and have-nots. Demonstrators call themselves "the 99 percent."
The report also found:
-The top 20 percent of the population earned 53 percent of after-tax income in 2007, as opposed to 43 percent in 1979. -The top 1 percent reaped a 17 percent share of all income, up from 8 percent in 1979.
-The bottom 20 percent reaped just 5 percent of after-tax income, versus 7 percent in 1979.
Lawmakers and presidential candidates are mulling overhauling the tax code - some propose a flat tax that critics say could magnify the income gap - and a congressional "supercommittee" is weighing options to cut the deficit.
President Barack Obama has toured the country promising to raise taxes on the wealthy in order to finance his jobs agenda, which includes continuing a payroll tax cut, boosting infrastructure spending and helping local governments avoid layoffs of teachers, police officers and firefighters.
In a speech Wednesday, Rep. Paul Ryan, R-Wis., the chairman of the House Budget Committee, decried Obama's moves as "class warfare" and said GOP policies would preserve "equality of opportunity."
"Telling people they are stuck in their current station in life, that they are victims of circumstances beyond their control, and that the government's role is to help them cope with it - well, that's not who we are," Ryan said at the conservative Heritage Foundation.