Greater Des Moines foreclosures dropped to 2.47 percent in September, down 0.8 percentage points from last year, real estate research firm CoreLogic Inc. said today. Foreclosure activity in the Des Moines-West Des Moines metropolitan area was lower than the national foreclosure rate, which was 3.25 percent in September. The number of delinquent mortgages also dropped, with 4.37 percent of loans at least 90 days overdue, compared with 4.56 percent last year.