Sales of existing homes rose in May, as increasingly affordable home prices and a first-time tax credit for first-time home purchasers attracted hesitant buyers, CNNMoney.com reported.

The National Association of Realtors (NAR) reported that sales of existing homes ticked up 2.4 percent last month to a seasonally adjusted annual rate of 4.77 million units compared with the downwardly revised rate of 4.66 million in April.

The sales fell short of experts forecasts of 4.82 million annual units, according to a consensus estimate of analysts compiled by Briefing.com, and are off 3.6 percent from the 4.95 million-unit pace 12 months ago.

The median price of homes sold in May was just $173,000, a 16.8 percent year-over-year drop.

Low mortgage rates and affordable home prices helped draw in hesitant buyers, said Lawrence Yun, NAR chief economist, in a prepared statement.

Yun said another likely boost was the $8,000 tax credit, which the Obama administration made available to qualified first-time home buyers.

The slight sales increase helped reduced the supply of homes on the market. Total housing inventory fell 3.5 percent to 3.8 million existing homes for sale. That’s a 9.6-month supply, down from a 10.1-month supply in April.

The sales increase “is less than expected because poor appraisals are stalling transactions,” Yun added. “Some contracts are falling through from faulty valuations that keep buyers from getting a loan.”

A report earlier this month stated that the number of home sale contracts signed in April far exceeded forecasts. Pending home sales are a forward-looking indicator, because many of the contracts take weeks or months to become completed deals.

Home prices may now be affordable enough to draw in more buyers, but “the real test for this theory will come next month,” said Bob Walters, chief economist at Quicken Loans Inc. “If the numbers remain strong, perhaps it is time to begin pondering if we have started to form a bottom in the housing market.”