American households piled on more debt between 2001 and 2004, while their net worth barely increased.

According to the Federal Reserve Board's most recent Survey of Consumer Finances, U.S. families took on 34 percent more debt from 2001 to 2004, while net worth during the same period increased just 1.5 percent.

The triennial survey, which asked questions on income, assets and debt, tracked roughly 4,500 families representing a cross section of the country.

The report said that as debt levels rose during the three-year period, families devoted more of their incomes to servicing debts, despite a general decline in interest rates.

In 2001, U.S. families carried a median debt load of $41,300 (in 2004 dollars), including mortgages, lines of credit, installment loans and credit-card balances. By 2004, the median debt load had climbed to $55,300, a 33.9 percent increase.

Kendall Oliphant, director of operations for Salt Lake-based Thredgold Economic Associates, said the survey offers a good history lesson, but it does not tell a lot about what is happening right now.

"The fact that it is talking about a time period where we were in recession and then a weak recovery period, that's not surprising that the numbers are a little bit ugly," said Oliphant, who added that in 2001 U.S. bankruptcies were up 19 percent.

Kelly Matthews, executive vice president and economist at Wells Fargo, said that while households are taking on more debt, appreciating home values have put homeowners in a solid financial position.

"In the period since that study has occurred," Matthews said, "real estate values and the improvement in our stock portfolios suggest to me that net worth is increasing and, I believe, increasing noticeably faster than aggregate debt levels."

Mortgage debt showed the largest percent increase over the 2001-2004 period, rising 27.3 percent. This type of debt, the report noted, peaks among families in the 45-54 age group and declines sharply among older age groups.

The report said that in 2004, 45 percent of U.S. families had a first-lien mortgage, 4.2 percent had a junior-lien mortgage and 8.6 percent had a home equity line of credit with a current balance.

For those borrowing against home equity, the median balance was $22,000 in 2004, up from $16,000 in 2001.

The survey said 46.2 percent of U.S. families carried credit card balances in 2004, a 1.8 percentage point increase from 2001. Overall, the median balance of credit card debt during the period rose 10 percent to $2,200.

The share of families with any type of debt climbed to 76.4 percent for a 1.3 percentage point increase over the 2001-2004 period.