ASHINGTON, Jan. 22 — Economic inequality increased markedly as the boom of the 1990's fizzled, even as incomes increased at almost every level, according to a detailed new survey by the Federal Reserve released today.

Conducted at the end of 2001, when the economy was in a recession, the survey compared wealth and income with levels of 1998. It suggests that the benefits of the economic boom were widespread but extremely uneven.

The wealth of those in the top 10 percent of incomes surged much more than the wealth of those in any other group. The net worth of families in the top 10 percent jumped 69 percent, to $833,600, in 2001 from $492,400 in 1998. By contrast, the net worth of families in the lowest fifth of income earners rose 24 percent, to $7,900.

The median accumulated wealth for families at the top was about 12 times that of lower-middle-income families through much of the 1990's. But in 2001, the median net worth of the top earners was about 22 times as great.

While income in the top 10 percent of households surged 19.3 percent from 1998 to 2001, income for the bottom fifth of households increased 14.4 percent.

The survey is compiled every three years and is based on interviews with more than 4,000 families. Its results come as President Bush proposes a plan to cut taxes $674 billion over 10 years. Opponents of the plan, which has as its centerpiece a proposal to eliminate most taxes on stock dividends, say most of the benefits would be showered on the richest taxpayers.

Administration officials respond that a large percentage of ordinary Americans now own stocks and would benefit from both tax-free dividends and any lift in market prices.

The survey provides some ammunition for both sides. It shows that wealth became more concentrated, but it also confirms that more than half of all families own stocks, either directly or through their mutual funds and pension plans.

A controversial element of the survey may be the part that deals with household debt.

American consumers provided much of the backbone for economic growth, but economists have long been worried that consumers ran up too much debt in the process.

The Fed's report contends that household debt is more benign than it seems. It noted that Americans did in fact borrow more in 2001 than in 1998 but said that their net worth rose even faster.

As a share of total family income, the Fed said, the aggregate debt burden of families in fact decreased to 12.5 percent in 2001 from 14 percent through most of the 1990's.

Even accounting for stock market declines after the survey was conducted, the Fed said, household wealth was still higher in 2001 than in 1998.

"Rising aggregate debt levels alone do not necessarily imply that conditions deteriorated at the level of individual families," the report said.

But at least some outside economists disputed that conclusion on several grounds.

They noted that in addition to a further stock market decline, unemployment rose after the survey was finished in December 2001. They also said that the survey understated signs of trouble that were already apparent.

Mark Zandi of Economy.com in West Chester, Pa., noted that the percentage of low-income households more than 60 days past due on a debt increased to 13.4 percent in 2001 from 12.9 percent in 1998.

Mr. Zandi said an abundance of newer data provided stronger evidence that lower-income households were under much more stress than before: personal bankruptcies, automobile repossessions, mortgage foreclosures and other indicators of bad debt all reached records in 2002.

The Fed calculations "clearly misrepresent the debt load as it existed in 2001 and even more clearly misrepresent the debt load as it exists now," Mr. Zandi said. "This is a problem that is going to get worse."

To be sure, the Fed survey also shows that even middle- and lower-income families benefited from the economic boom. Home ownership increased, even though housing prices climbed 25 percent. Stock ownership reached 51 percent of all households.

The average income of African-American families surged 20 percent from 1998 to 2000. But for reasons that Fed officials had difficulty explaining today, the average income for all nonwhite and Hispanic families barely increased.

"I am alarmed and disheartened by the growth in inequality in this report," said Jared Bernstein, senior economist at the Economic Policy Institute, a liberal research group based in Washington. "I am especially mindful of this problem, given the administration's tax proposals. I hope policy makers take this data into consideration."