WASHINGTON (AP) - Americans stepped up their home-buying for a third straight month in July, as sales accelerated to the strongest pace in eightyears.

The National Association of Realtors said Thursday that sales of existing homes rose 2 percent last month to a seasonally adjusted annual rate of 5.59 million, the fastest rate since February 2007. Sales have jumped 9.6 percent over the past 12 months, while the number of listings has declined 4.7percent.

Steady job growth and relatively low mortgage rates have convinced current homeowners to purchase homes, while first-time buyers remain scarce. The housing market contains a mere 4.8 months' supply of homes, meaning that prices are rising for an increasingly narrow set ofproperties.

The slow six-year recovery from the Great Recession has finally revitalized the housing market. Home sales have soared in recent months, as more current homeowners have returned to the real estate market for an upgrade or to downsize as they approach retirement. Yet the upswing also reflects increasing problems with affordability that have left first-time buyer on thesidelines.

"When first-time homebuyers compete with people who are more qualified borrowers that have additional cash, they tend to lose," said Budge Huskey, chief executive of the real estate brokerage ColdwellBanker.