WASHINGTON (AP) — U.S. long-term mortgage rates declined this week as growing concern over the economic impact of China's viral outbreak spurred a steep downturn in global stock markets.

Mortgage buyer Freddie Mac says the average rate for a 30-year fixed-rate mortgage fell to 3.45% from 3.49% last week. Rates are far below year-ago levels: the benchmark 30-year loan averaged 4.35% a year ago.

The average rate on a 15-year fixed mortgage slipped to 2.95% from 2.99% last week. The slide in stock prices pushed investors to buy up U.S. Treasury securities, viewed as a safe haven in the event of an economic downturn.