The Mortgage Bankers Association said U.S. mortgage activity fell slightly in the week ending Friday, despite a drop in long-term interest rates. After rising the previous week, mortgage activity fell 2.4 percent. The trade group\'s Refinancing Index also dropped, falling 3.1 percent from the previous week. Interest rates for 30-year, fixed-rate conforming mortgages fell from 4.16 percent to to 4.1 percent with average points unchanged at 0.43. Rates for 15-year, fixed-rate contracts fell from 3.4 percent to 3.37 percent. Points for 15-year loans fell from 0.41 to 0.37.