House sales spiked nearly 24 percent in May, with 1,498 closed transactions, compared with 1,212 in April, the Des Moines Area Association of Realtors said. The median sales price increased 3.3 percent in May to $205,000. The number of pending sales dropped to 1,546 in May from 1,755 in April. Houses that sold last month had been on the market an average 57 days, compared with 60 in April. The number of properties currently for sale increased 9.3 percent to 3,417 active listings from 3,127 in April.