WASHINGTON (AP) — Construction firms broke ground on more apartment complexes in September, pushing up the pace of U.S. homebuilding.Housing starts rose 6.3 percent to a seasonally adjusted annual rate of 1.017 million homes, the Commerce Department said Friday. Almost all of the gains came from apartment construction — a volatile category — which increased 18.5 percent after plunging in August.The sluggish recovery and meager wage growth has left more Americans renting instead of owning homes. Apartment construction has surged 30.3 percent over the past 12 months.Starts for single-family houses rose just 1.1 percent in September, contributing to an 11 percent gain during the past 12 months.Applications for building permits, a good sign of future activity, increased 1.5 percent to an annual rate of 1.018 million.