COSTA MESA, Calif. — A new report from Experian Automotive has found that U.S. car loans 60 days past due jumped 17 percent year-over-year in the fourth quarter of 2008, threatening further restrictions on subprime automotive finance.

Although 60-day delinquencies now represent barely more than 1 percent of all auto loans, such losses can convince lenders to finance fewer credit-challenged customers or raise those buyers' cost on each deal. That can be accomplished by raising interest rates or requiring larger down payments.

"A lot of lenders made changes in 2008 to their lending practices," Melinda Zabritski, Experian's director of automotive credit, told USA Today. "I expect to see that holding steady for the rest of this year."

Experian's report also found that:

• The average U.S. new-vehicle loan was $24,444 in the fourth quarter of 2008, down $338 year-over-year.

• The average U.S. used-vehicle loan was $15,904 in the fourth quarter of 2008, down $678 year-over-year.

• Delinquency rates are highest in Mississippi, the District of Columbia, Alabama, Georgia and South Carolina.

• Delinquencies are lowest in North Dakota, Arkansas, South Dakota, Montana and Wyoming.