Existing-home sales rose sharply in December, when sales increased for the fifth time in the past six months, according to the National Association of Realtors.

Existing-home sales, which are completed transactions that include single-family, townhomes, condominiums and co-ops, rose 12.3 percent to a seasonally adjusted annual rate of 5.28 million in December from an upwardly revised 4.70 million in November, but remain 2.9 percent below the 5.44 million pace in December 2009.

Lawrence Yun, NAR chief economist, said sales are on an uptrend. “December was a good finish to 2010, when sales fluctuate more than normal. The pattern over the past six months is clearly showing a recovery,” he said. “The December pace is near the volume we’re expecting for 2011, so the market is getting much closer to an adequate, sustainable level. The recovery will likely continue as job growth gains momentum and rising rents encourage more renters into ownership while exceptional affordability conditions remain.”

The national median existing-home price for all housing types was $168,800 in December, which is 1.0 percent below December 2009. Distressed homes rose to a 36 percent market share in December from 33 percent in November, and 32 percent in December 2009.

“The modest rise in distressed sales, which typically are discounted 10 to 15 percent relative to traditional homes, dampened the median price in December, but the flat price trend continues,” Yun explained.

Total housing inventory at the end of December fell 4.2 percent to 3.56 million existing homes available for sale, which represents an 8.1-month supply at the current sales pace, down from a 9.5-month supply in November.

NAR President Ron Phipps, broker-president of Phipps Realty in Warwick, R.I., said buyers are responding to very good affordability conditions despite tight mortgage credit. “Historically low mortgage interest rates, stable home prices, and pent-up demand are drawing home buyers into the market,” Phipps said. “Recent home buyers have been successful with very low default rates, given the outstanding performance for loans originated in 2009 and 2010.”

According to Freddie Mac, the national average commitment rate for a 30-year, conventional, fixed-rate mortgage rose to 4.71 percent in December from 4.30 percent in November; the rate was 4.93 percent in December 2009.

A parallel NAR practitioner survey shows first-time buyers purchased 33 percent of homes in December, up from 32 percent in November, but are below a 43 percent share in December 2009.

Investors accounted for 20 percent of transactions in December, up from 19 percent in November and 15 percent in December 2009; the balance of sales were to repeat buyers. All-cash sales were at 29 percent in December, compared with 31 percent in November, but up from 22 percent a year ago. “All-cash sales have been consistently high at about 30 percent of the market over the past six months,” Yun said.

Single-family home sales jumped 11.8 percent to a seasonally adjusted annual rate of 4.64 million in December from 4.15 million in November, but are 2.5 percent below the 4.76 million level in December 2009. The median existing single-family home price was $169,300 in December, down 0.2 percent from a year ago.

Existing condominium and co-op sales surged 16.4 percent to a seasonally adjusted annual rate of 640,000 in December from 550,000 in November, but remain 5.2 percent below the 675,000-unit pace one year ago. The median existing condo price was $165,000 in December, which is 7.4 percent below December 2009.

Regionally, existing-home sales in the Northeast jumped 13.0 percent to an annual pace of 870,000 in December but are 5.4 percent below December 2009. The median price in the Northeast was $237,300, which is 1.4 percent below a year ago.

Existing-home sales in the Midwest rose 11.0 percent in December to a level of 1.11 million but are 4.3 percent below a year ago. The median price in the Midwest was $139,700, up 3.3 percent from December 2009.

In the South, existing-home sales increased 10.1 percent to an annual pace of 1.97 million in December but are 2.5 percent below December 2009. The median price in the South was $148,400, unchanged from a year ago.

Existing-home sales in the West surged 16.7 percent to an annual level of 1.33 million in December but remain 1.5 percent below December 2009. The median price in the West was $204,000, down 5.6 percent from a year ago.