U.S. homes sold in September rose at their fastest clip this year, yet the housing market has yet to fully shake off a slowdown that began in the middle of 2013. The National Association of Realtors says sales of existing homes rose 2.4 percent to a seasonally adjusted annual rate of 5.17 million homes. Still, the sales rate has dropped 1.7 percent over the past 12 months. Investors have retreated from the market over the past year. Their departures are being offset by existing homeowners who are upgrading to more expensive properties or downsizing after having raised their children. Rising prices through much of 2013, weak income growth and tighter credit standards have priced out many would-be buyers. Median home prices rose 5.6 percent over the past 12 months to $209,700.