About 1 in 11 American mortgages were past due or in foreclosure at the end of March, according to a report released on Thursday, a figure that is rising fast as home prices fall and the job market weakens.

The first three months of 2008 marked the worst quarter for American homeowners in nearly three decades, according to the report, issued by the Mortgage Bankers Association. The rate of new foreclosures and past-due payments surged to their highest level since 1979, when the group first started collecting the data.

All told, about 8.8 percent of home loans were past due or in foreclosure, or about 4.8 million loans. That is up from 7.9 percent at the end of December. (About a third of American homeowners do not have mortgages.)

Delinquency and foreclosure rates started rising from historically low levels in late 2006 and have picked up speed in nearly every quarter since. Analysts say at first past due mortgages represented mostly high-risk loans made to borrowers with blemished, or subprime, credit. Now, as the economy has weakened and home prices have fallen in many parts of the country, homeowners with better loans are also falling behind.