SOUTH PORTLAND — Sales of existing, single-family homes in Maine fell 24 percent in April compared to a year ago.

The Maine Association of Realtors said today that real estate agents sold 758 homes during the month, down from 994 a year earlier. The median sales price of $160,750 was nearly 3 percent lower than a year ago.

The association says the numbers fell sharply because last year’s sales were boosted by the federal homebuyer tax credit, which expired at the end of April 2010.

For the three-month period from February through April, existing home sales in Maine were down 18 percent from the same period last year.