WASHINGTON (AP) — Long-term U.S. mortgage rates fell this week to their lowest levels of the year. The benchmark 30-year rate dipped below the key 4 percent mark.

Mortgage buyer Freddie Mac says the average rate on 30-year fixed-rate home loans tumbled to 3.95 percent from 4.02 percent last week. The rate stood at 3.64 percent a year ago and averaged 3.65 percent in 2016, the lowest level in records dating to 1971.

The rate on 15-year mortgages slipped to 3.19 percent from 3.27 percent last week.