U.S. mortgage interest rates declined in the latest week, according to Freddie Mac, as investors worried about international trade wars. The average rate on a 30-year fixed-rate mortgage dropped to 4.10% with an average 0.5 point during the week ended May 9, down from 4.14% the week before. The decrease is more dramatic in a yearly comparison; the average rate a year ago was much higher at 4.55%.