For the three months ended Sept. 30, 6.25% of U.S. mortgage loans were 60 or more days past due, TransUnion says. That's up 58% from 3.96% a year ago.

Being two months behind is considered a first step toward foreclosure, because it's so hard to catch up with payments at that point.

The rate was up 7.6% from the second quarter. That's a much smaller jump than the 11.3% rise in the second quarter from the first, and the 14% leap the quarter before that.

While the slowing growth rate is a positive sign, the increase shows there's still a lot of problem mortgages out there, says F.J. Guarrera, vice president of TransUnion's financial services division. The company doesn't expect the figure to start declining until the middle of next year.

Two things must get better before mortgage delinquency rates start reversing themselves, he said: home values and unemployment. "Until we see improvement in both of those areas, it's possible that it will take longer for delinquency to improve," Guarrera said.

The statistics, culled from TransUnion's database of 27 million consumer records, show that mortgage delinquencies remain highest in the four states where the crisis hit hardest.

In Nevada, the rate reached 14.5%, up from 7.7% a year ago.
In Florida, the rate was 13.3%, up from 7.8% last year.
In Arizona, the rate hit 10.4%, up from 5.5% in 2008.
In California, the rate jumped to 10.2%, from 5.8% last year.

North Dakota remained the state where mortgage holders most often paid on time, with just 1.7% delinquency, up from 1.4% last year.

TransUnion expects delinquency to rise to just short of 7% for the fourth quarter, compared with 4.6% for the 2008 fourth quarter. The rate may reach 16% in Nevada. Those states with the highest delinquency and foreclosure rates will likely continue to see depressed housing prices.

The average mortgage debt per borrower nationwide edged up to $193,121 in the third quarter, from $192,287 last year. The District of Columbia had the highest average mortgage debt per borrower at $359,788. The lowest average mortgage debt per borrower was in West Virginia at $97,265.