U.S. mortgage activity rose last week as long-term interest rates were mostly lower, the Mortgage Bankers Association said Wednesday. The association said mortgage activity rose 7 percent in the week while refinancing activity rose 8 percent in the week ending Friday. Interest rates for 30-year, fixed-rate conforming mortgages decreased from 3.6 percent to 3.59 percent during the week, the lowest rate since December 2012. Points for 30-year conforming loans rose from 0.3 to 0.33. The average interest rate for 30-year contracts on jumbo loans -- larger than $417,500 -- fell from 3.8 percent to 3.79 percent. Points for 30-year jumbo loans fell from 0.29 to 0.2. Interest rates for 15-year, fixed-rate mortgages fell to the lowest rate in the history of the MBA survey with rates falling from 2.84 percent to 2.81 percent, with points rising from 0.26 to 0.29. The average rate for 30-year loans backed by the Federal Housing Administration rose from 3.34 percent to 3.35 percent with points rising from 0.37 to 0.57. The average rate for short-term, adjustable-rate mortgages dropped in the week from 2.55 percent to 2.53 percent, also reaching the lowest rate in the history of the survey. Points for short-term adjustable-rate loans fell from from 0.22 to 0.15, the MBA said.