The average long-term U.S. mortgage rate climbed for the fifth straight week, reaching its highest level in nearly seven months, another setback for home shoppers in the midst of the spring homebuying season. The benchmark 30-year fixed rate mortgage rate rose to 6.46% from 6.38% last week, mortgage buyer Freddie Mac said Thursday. One year ago, the rate averaged 6.64%. The last time the average rate was higher was Sept. 4, when it was at 6.5%. When mortgage rates rise, they can add hundreds of