Sales of existing U.S. homes rose in August, according to the National Association of Realtors, and home prices rose again for the sixth month in a row.

Total sales of existing single-family homes, townhomes, condo, and co-ops grew by 7.8 percent to a seasonally adjusted annual rate of 4.82 million in August, up from July’s 4.47 million, and also up 9.3 percent from one year earlier.

At the same time the national median price rose to $187,400, a 9.4 percent gain from August 2011, although down slightly from July’s $187,800. August marks the sixth consecutive month of year-over-year price gains. Such a long streak has not been seen since the period between December 2005 and May 2006.

“The housing market is steadily recovering with consistent increases in both home sales and median prices. More buyers are taking advantage of excellent housing affordability conditions,” said Lawrence Yun , NAR chief economist in a statement. “Inventories in many parts of the country are broadly balanced, favoring neither sellers nor buyers. However, the West and Florida markets are experiencing inventory shortages, which are placing pressure on prices.”

Inventory increased 2.9 percent to 2.47 million homes on the market, representing a 6.1-month supply at the current sales pace. Compared with last year at this time, inventory is down 18.2 percent.

Investors snapping up foreclosures continue to be a big driving factor in the market, as 27 percent of August transactions were all-cash purchases. And 22 percent of sales were distressed homes – foreclosures or short sales.

First-time homebuyers accounted for 31 percent of the purchases, down from 34 percent in July. Some potential buyers continue to face daunting mortgage loan requirements that are keeping them out of the market.

“The strengthening housing market is occurring even with difficult mortgage qualifying conditions, which is testament to the sizable stored-up housing demand that accumulated in the past five years,” Yun added.