Long-term US mortgage rates were lower after a four-week stall, the Federal Home Loan Mortgage Corp. said Thursday. Rates for 30-year, fixed-rate mortgages dropped from 3.56 percent with an average 0.8 point to 3.51 percent, Freddie Mac said. Rates for 15-year contracts dropped in the latest survey from 2.77 percent to 2.76 percent with an average 0.8 point. One point is equal to 1 percent of the amount of the loan and is typically paid up front. It includes a corresponding discount on the loan\'s long-term interest rates. Interest rates for five-year adjustable rate mortgages slid from 2.64 percent with an average of 0.6 points to 2.61 percent. One-year adjustable rate mortgages using 10-year bonds as a benchmark, averaged 2.64 percent with 0.4 point in the week, down from 2.65 percent in the previous week. Rates are moving lower just before the spring home-buying season, Freddie Mac noted.