U.S. mortgage activity rose 11.1 percent in the week, as interest rates for long-term contracts fell, the Mortgage Bankers Association said Wednesday. The trade group said mortgage refinancing activity also rose, climbing 12 percent in the week from the previous week. In the week ending Friday, interest rates for 30-year, fixed-rate conforming mortgages fell from 3.78 percent to 3.75 percent with points rising from 0.37 to 0.44. The average interest rate for 15-year fixed-rate mortgages also fell, dropping from 3.1 percent to 3.07 percent, with points rising from 0.37 to 0.38 in the week.