Jan. 28, 2016 11:40 AM ET AP, Associated Press 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. Gerry Broome FILE - In this Tuesday, June 9, 2015, file photo, a sold sign is displayed in the yard of a newly constructed home in the Briar Chapel community in Chapel Hill, N.C. On...