WASHINGTON (AP) — Average long-term U.S. mortgage rates edged lower this week for a third straight week.

Mortgage buyer Freddie Mac said Thursday the average rate on a 30-year fixed-rate mortgage slipped to 3.93 percent from 3.95 percent a week earlier. The average rate on 15-year fixed-rate mortgages eased to 3.16 percent from 3.18 percent.

The key 30-year rate was above its level of a year ago, 3.89 percent. Despite the recent declines, the rate has increased significantly overall since the end of October, when it stood at 3.76 percent.

The Federal Reserve is widely expected to raise its key short-term interest rate at its policymaking meeting on Dec. 15-16. It would be the Fed's first interest rate hike in nearly a decade.

The expectation was bolstered Wednesday, when Fed Chair Janet Yellen indicated that the U.S. economy is on track for an interest rate increase this month, though she was careful to point out that the Fed will need to review any upcoming data before making a final decision.

Most notable among those data is the government's November jobs report, which comes out Friday. Economists forecast that U.S. employers created 200,000 jobs last month and the unemployment rate remained steady at 5 percent.

The yield on the 10-year Treasury bond, which mortgage rates have been tracking, fell to 2.18 percent Wednesday from 2.23 percent a week earlier. Yields on the U.S. government bonds move in the opposite direction of the bonds' prices. The yield jumped back up to 2.26 percent Thursday morning.

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 declined to 0.6 point from 0.7 point last week. The fee for a 15-year loan eased to 0.5 point from 0.6 point.

The average rate on five-year adjustable-rate mortgages fell to 2.99 percent from 3.01 percent; the fee was unchanged at 0.5 point. The average rate on one-year ARMs rose to 2.61 percent from 2.59 percent; the fee held at 0.3 point.