The foreclosure rate in Greater Des Moines dropped in November, real estate analytics firm CoreLogic Inc. said. Foreclosures made up 2.34 percent of active mortgages, down from 2.52 percent in November 2011. The number of mortgages that were 90 or more days past due also improved, dropping to 4.29 percent in November from 4.75 percent a year ago, CoreLogic said. The national foreclosure rate in November was 2.97 percent.