WASHINGTON (AP) — Average long-term U.S. mortgage rates rose slightly this week after four straight weeks of declines, while remaining near historically low levels.

Mortgage company Freddie Mac said Thursday the nationwide average for a 30-year mortgage edged up to 3.66 percent from 3.63 percent last week. The new average rate is still at its lowest level since May 2013.

The rate for the 15-year loan, a popular choice for people who are refinancing, increased to 2.98 percent from 2.93 percent last week.

A year ago, the average 30-year mortgage stood at 4.32 percent and the 15-year mortgage at 3.40 percent. Mortgage rates have remained low even though the Federal Reserve in October ended its monthly bond purchases, which were meant to hold down long-term rates.

The Fed sent a message Wednesday, after its latest policy meeting, that it will be “patient” in raising interest rates from record lows despite the steadily brightening outlook for the economy. The central bank indicated that no rate hike is likely soon because inflation remains well below its target rate.

On Tuesday, the Commerce Department reported that sales of new U.S. homes accelerated strongly in December, a sign that home-buying may improve this year after a lackluster 2014.

The growth last month pointed to rising sales in 2015, buoyed by the combination of sharply lower mortgage rates and strong hiring by businesses in recent months. Home prices are rising at a slower pace, improving affordability for would-be buyers.

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 was 0.6 point, down from 0.7 point last week. The fee for a 15-year mortgage fell to 0.5 point from 0.6 point.

The average rate on a five-year adjustable-rate mortgage increased to 2.86 percent from 2.83 percent. The fee was unchanged at 0.4 point.

For a one-year ARM, the average rate ticked