WASHINGTON (AP) — Average long-term U.S. mortgage rates dropped this week to their lowest levels since May, in a week marked by turmoil in global markets that was stoked by economic developments in China.

Mortgage giant Freddie Mac says the average rate on a 30-year fixed-rate mortgage fell to 3.84 percent from 3.93 percent a week earlier. The benchmark rate hasn't been that low since May 21.

The rate on 15-year fixed-rate mortgages declined this week to 3.06 percent from 3.15 percent.

The panic selling and extreme gyrations in stock markets sent investors to the safety of U.S. government bond prices, raising their prices and dampening their rates. Mortgage rates often track the yield on the 10-year Treasury bond, which dipped below 2 percent on Monday. The yield recovered to 2.18 percent Wednesday.