The number of homes sold and median price were up in the Austin-Round Rock area in September compared to the previous year, according to Austin Board of Realtors data released Tuesday.

The report, which covers sales in Travis, Williamson, Hays, Bastrop and Caldwell Counties, showed home sales in the Austin-Round Rock metro area rose 1.3 percent year-over-year in September 2016 and the median home price across the five counties rose 7.5 percent to $275,250. The report also shows single-family home sales dropped 4.5 percent in September in the City of Austin and the median home price jumped 10.6 percent to $345,000. Across the five-county Central Texas region, home sales were up 6.1 percent from September 2015.

Less than one in three homes sold in the Austin-Round Rock metro area and less than one in five homes sold in Central Texas in September were sold within Austin’s city limits, the report said. ABoR pointed to the strain on Austin’s infrastructure as a reason for the trend.

“Housing is at the center of all economic development,” said Aaron Farmer, 2016 President of the Austin Board of Realtors in a release. “Nowhere is this more evident than at the intersection of housing affordability and mobility. As more and more homebuyers look outside of Austin’s city limits to find an affordable home, our region’s infrastructure is increasingly strained and the overall costs of homeownership rise because of the increased cost to commute.”

ABoR announced its support of the city’s $720 million mobility bond proposition in June, which the city said would ease congestion.

“Both Austin’s current housing stock and infrastructure are not sustainable for our region’s projected population growth, which is expected to double by 2040,” said Farmer. ABoR added single-family homes are also spending less time on the market. In September 2016, homes in Williamson and Hays Counties were on the market an average of 44 and 48 days, respectively.