Sales of new U.S. single-family homes unexpectedly fell in July to a nine-month low in a sign the housing market was cooling and could give less support to the overall economy.

The Commerce Department said on Thursday new home sales decreased 1.7 percent to a seasonally adjusted annual rate of 627,000 units last month, the lowest level since October 2017. June’s sales pace was revised up to 638,000 units from the previously reported 631,000 units.