WASHINGTON » The average U.S. rate on a 30-year fixed mortgage has fallen to near its record low set earlier this month.

The rate on the most popular mortgage dipped to 3.37 percent from 3.39 last week, mortgage buyer Freddie Mac said today. Two weeks ago, the rate reached 3.36 percent, its lowest level on records dating to 1971.

The average rate on the 15-year fixed mortgage, often used for refinancing, set a record low of 2.66 percent, down from last week’s 2.7 percent.

Cheaper mortgages are helping fuel a modest but steady housing recovery.

The average rate on the 30-year loan has remained below 4 percent all year. And rates have fallen even further since the Federal Reserve started buyingmortgage bonds in September to try to encourage more borrowing and spending.

The Fed said it would continue buying bonds until the job market shows substantial improvement. When home prices rise, people tend to feel wealthier and spend more freely. And consumer spending drives nearly 70 percent of economic activity.

Home sales have risen from last year, and prices are rising more consistently in most areas. Builders are more confident and starting more homes. Lower rates have also persuaded more people to refinance. That typically leads to lower monthly mortgage payments and more spending.

Builders last month started construction on single-family houses and apartments at the fastest rate in more than four years, the Commerce Department said Wednesday. And they laid plans to build homes at an even fast pace in coming months — a signal of their confidence that the housing rebound will last.

Other recent reports have shown marked improvement in the housing market five years after the bubble burst.

Still, the housing market has a long way to a full recovery. And many people are unable to take advantage of the low rates, either because they can’t qualify for stricter lending rules or they lack the money to meet larger down payment requirements.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country on Monday through Wednesday 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 30-year loans was 0.7 point, unchanged from last week. The fee for 15-year loans also held steady at 0.6 point.

The average rate on a one-year adjustable-rate mortgage edged up to 2.60 percent from 2.59 percent. The fee for one-year adjustable rate loans was stable at 0.4 point.

The average rate on a five-year adjustable-rate mortgage rose to 2.75 percent from 2.73 percent. The fee was unchanged at 0.6 point.