WASHINGTON (AP) — Long-term U.S. mortgage rates didn't budge this week, remaining at historically low levels that continue to lure prospective home buyers.

Mortgage giant Freddie Mac said Thursday that the average for the benchmark 30-year fixed-rate mortgage was 3.43 percent, unchanged from last week. The average rate is down from 3.84 percent a year ago, and is close to its all-time low of 3.31 percent in November 2012.

The 15-year fixed mortgage rate stayed at 2.74 percent.

Financial markets are awaiting a speech by Federal Reserve Chair Janet Yellen Friday at an annual conference of central bankers for clues on a possible interest-rate increase. The Fed is expected to hold off raising rates at its meeting next month, but Yellen's comments may provide a hint on the likelihood of a future increase.

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 rose to 0.6 point this week from 0.5 point last week. The fee for a 15-year loan was unchanged from last week at 0.5 point.

Rates on adjustable five-year mortgages averaged 2.75 percent, down from 2.76 percent last week. The fee remained at 0.4 point.