NEW YORK – The percentage of auto loans that were past due 60 days or more rose 11.5 percent in the second quarter compared to last year, according to credit reporting agency TransUnion.

The rate rose to 0.68 percent of outstanding loans, from 0.61 percent in 2007’s second quarter.

Delinquencies edged up 0.03 percent from the first quarter of 2008.

Peter Turek, automotive vice president in TransUnion’s financial services group, said auto-loan delinquencies tend to be cyclical, with fourth quarter typically showing the fewest problematic payments, and rising in the first and second quarters.

Delinquencies were highest in Washington, D.C., at 1.41 percent, and Mississippi, at 1.25 percent. The states with the lowest auto-loan delinquency rates were Alaska, at 0.22 percent, North Dakota, at 0.30 percent and Wyoming, at 0.41 percent.

Average auto debt also increased for the second quarter, up about 2 percent to $12,869, from $12,630 in the year-ago quarter. Turek said part of this increase reflects the ongoing housing slump.

“In some states there’s a lack of home equity,” he noted. “Folks have less access to home equity to finance auto purchases,” which has led to more people taking out car loans.

Nevada had the highest average auto loan, at $16,033, followed by Washington, D.C., at $15,369. The lowest average was in Nebraska, at $10,681.

Maine, North Dakota and West Virginia saw the steepest increases in average loan size.

TransUnion expects average auto debt to continue to rise as more people seek to buy fuel-efficient cars. The delinquency rate is also likely to rise, Turek said, reflecting both seasonal trends and the wider slowdown in the economy.