Greater Des Moines foreclosure rates dropped to 1.56 percent of active mortgages in January, down from 2.36 percent a year ago, real estate analytics firm CoreLogic Inc. said today. The national foreclosure rate was 1.97 percent in January. The rate of mortgages that were 90 or more days delinquent declined in Greater Des Moines to 3.5 percent from 4.3 percent last year.