WASHINGTON (AP) – Average long-term U.S. mortgage rates were unchanged to slightly higher this week after declining the previous week. Mortgage buyer Freddie Mac says the average rate on a 30-year, fixed-rate mortgage was steady at 3.71 percent. The benchmark rate also remained close to the 3.70 percent level it marked a year ago. The average rate on 15-year fixed-rate mortgages edged up to 2.98 percent from 2.96 percent last week.