WASHINGTON » Average U.S. rates on fixed mortgages fell again to new record lows. The decline suggests the Federal Reserve’s stimulus efforts may be having an impact on mortgage rates.

Mortgage buyer Freddie Mac said today that the rate on the 30-year loan dropped to 3.40 percent. That’s down from last week’s rate of 3.49 percent, which was the lowest since long-term mortgages began in the 1950s.

The average on the 15-year fixed mortgage, a popular refinancing option, fell to 2.73 percent, down from the record low of 2.77 percent last week.

The Fed is spending $40 billion a month to buy mortgage-backed securities. The goal is to lower mortgage rates and help the housing recovery. Fed Chairman Ben Bernanke says the program will continue until there is substantial improvement in the job market.

Some economists expect mortgage rates to fall even further because of the Fed’s bond purchases.

The housing market already is benefiting from the lowest mortgage rates on record. Sales of both previously occupied and newly built homes in the U.S. are up from last year. Home prices are rising more consistently. And builders are more confident in the market and are starting to build more homes.

The broader economy is also likely to benefit from a revival in the housing market. When home prices rise, Americans typically feel wealthier and spend more.

Still, the housing market has a long way back. Sales and construction rates remain below healthy levels.

And some economists question whether lower rates will make much of a difference. The average rate on the 30-year fixed mortgage has been below 4 percent since early December. So most people who can qualify have likely already taken advantage of the lower rates.

Many people who would like to refinance or buy a home can’t because they fail to meet stricter lending requirements or don’t have enough money to make a down payment.

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

The average does not 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 0.6 point, unchanged from last week. The fee for 15-year loans also held steady at 0.6 point.

The average rate on one-year adjustable-rate mortgages dipped to 2.60 percent from 2.61 percent. The fee for one-year adjustable rate loans was unchanged at 0.4 point.

The average rate on five-year adjustable-rate mortgages fell to 2.71 percent from 2.76 percent. The fee remained at 0.6 point.