Sales of new U.S. single-family homes unexpectedly fell in May, falling to the lowest level in a year as supply constraints have pushed up prices.

The Commerce Department said on Wednesday that new home sales tumbled 5.9 percent to a seasonally adjusted annual rate of 769,000 units last month, that is the first reading below 800,000 since May of 2020.

Economists polled by Econoday had forecast that new home sales would increase to a rate of 868,000 units in March. April’s sales figure was revised down to 817,000 from the preliminary 863,000.

New home sales make up just 12 percent or so of the market for homes. But these sales carry a large economic impact because house building is labor-intensive and new homes have to be outfitted with appliances and furniture.