WASHINGTON (AP) - Average long-term U.S. mortgage rates fell this week for a fourth straight week amid persisting turmoil in stock markets and global economic worries.

WASHINGTON (AP) Average long-term U.S. mortgage rates fell this week for a fourth straight week amid persisting turmoil in stock markets and global economic worries.

Mortgage buyer Freddie Mac says the average rate on a 30-year fixed-rate mortgage slipped to 3.79 percent from 3.81 percent a week earlier. That means it stays below the symbolically significant 4 percent level. The rate has increased from its 3.66 percent average a year ago but remains well below its historic average of 6 percent.

The average rate on 15-year fixed-rate mortgages declined to 3.07 percent from 3.10 percent.

The Federal Reserve sounded a note of concern Wednesday about how global pressures could affect a slowing U.S. economy. Fed policymakers kept a key interest rate unchanged following their meeting this week.