Despite significant gains in 2004, the total income Americans reported to the tax collector that year, adjusted for inflation, was still below its peak in 2000, data show.
Since 2004, the Census Bureau has found, the income of the typical American household has grown along with the rise in average incomes but at a slow pace that, until recent months, had barely kept ahead of inflation.
The tax data, while not as up to date, helps spell out whose incomes were most affected in the recent downturn and why.
The overall decline in income came despite a series of tax cuts that President Bush and congressional Republicans promoted as the best way to stimulate both short- and long-term growth after the Internet bubble burst on Wall Street in 2000 and the economy fell into a brief recession in 2001.
A White House spokesman, Tony Fratto, said the decline was a predictable result of "what we all know now was a bubble economy with inflated asset values, which is why $7-trillion of equity in the stock markets evaporated."
Incomes in 2004 did rise above those in 2003, with an overall average gain of 6.8 percent. The average year-over-year increases from 2003 to 2004 ranged from 1.8 percent for the poorest fifth of Americans to a 27.5 percent increase for the top 10th of 1 percent.