Average long-term U.S. mortgage rates fell this week, marking a 13th straight week below 4 percent and offering an enticement for potential homebuyers.

Mortgage giant Freddie Mac said Thursday the average rate on a 30-year fixed-rate mortgage declined to 3.79 percent from 3.82 percent a week earlier. The rate on 15-year fixed-rate mortgages eased to 2.98 percent from 3.03 percent.

The rates are well below last year’s levels. A year ago, the average 30-year mortgage rate was 3.82 percent, while the rate for 15-year loans was 3.08 percent.

The low rates and steady job gains have helped the real estate market reach what appears to be a stable plateau in recent months. Data issued Thursday by the National Association of Realtors showed that Americans snapped up more homes in September, suggesting that the housing sector remains insulated from global economic turmoil. Still, first-time buyers remain scarce and relatively few properties are being listed for sale, capping the potential growth of the sector.

Sales of existing homes jumped 4.7 percent last month to a seasonally adjusted annual rate of 5.55 million.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country at the beginning of each week. The average doesn’t include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for a 30-year mortgage held steady from last week at 0.6 point. The fee for a 15-year loan declined to 0.5 point from 0.6 point.

The average rate on five-year adjustable-rate mortgages rose to 2.89 percent from 2.88 percent; the fee was unchanged at 0.4 point. The average rate on one-year ARMs jumped to 2.62 percent from 2.54 percent; the fee was steady at 0.2 point.

(AP)