WASHINGTON (AP) — Fixed mortgage rates were mostly unchanged this week as credit markets showed little reaction to Washington's impasse over raising the federal government's borrowing limit.

Freddie Mac reported Thursday that the average rate on the 30-year fixed loan ticked up to 4.55 percent from 4.52 percent a week ago. That's slightly above this year's low of 4.49 percent.

The average rate on the 15-year fixed loan was unchanged at 3.66 percent, just above the yearly low of 3.65 percent.

Mortgage rates typically track the yield on the 10-year Treasury note. Yields have been stable, even though Congress and the Obama administration are days away from a potential default on the government's debt.

Low mortgage rates and depressed home prices have done little to revive the struggling housing market. Many people simply can't take advantage of the historically low rates because of tighter lending standards and bigger required down payments.

Other potential homebuyers are holding off, concerned that housing prices will continue to fall.

Few economists expect the housing market to rebound before 2013.

To calculate average mortgage rates, Freddie Mac collects rates from lenders across the country on Monday through Wednesday of each week.

The average rate on a five-year adjustable-rate mortgage edged down to 3.25 percent this week from 3.27 percent last week. The 3.25 percent was close to the record low of 3.22 set last month for this mortgage. The records go back to 2005.

The average rate for one-year adjustable-rate loans dipped to 2.95 percent, from 2.97 percent last week. The 2.95 percent matched the record low set two weeks ago.

The rates do not include extra fees known as points. One point is equal to 1 percent of the total loan amount.

The average fee for the 30-year loan was 0.8 point, up from 0.7 last week. Average fees for the 15-year fixed loan and the one-year ARM were unchanged at 0.7 and 0.5, respectively. The average fee for the five-year ARM rose to 0.6 from 0.5 last week.