The number of Greater Des Moines house sales dropped in September to 1,043 from 1,392 in August, the Des Moines Area Association of Realtors said today. The median sales price also took a dip, dropping 2.6 percent to $202,500 over the period, but remained above the $184,200 price from September 2017. Houses sold last month after being on the market an average of 57 days, a 26 percent increase from August and a 5 percent drop from last year. Inventory last month was steady at 3,903 active listings.