The number of sales of Manhattan townhouses jumped by nearly a third in 2010, while the average sales price climbed more than 9%—mostly due to an increase in the market share of single-family houses—according to Prudential Douglas Elliman and appraisal firm Miller Samuel Inc.

The number of sales of one- to five-family properties totaled 197 last year, up from 149 transactions in 2009, for an increase of 32.2%. Last year’s figure is still a far cry from the peak of the market in 2007, when there were 343 transactions. It’s also below the annual average over the past decade—246 transactions.

The average sales price in 2010 was $5.47 million, up from $5.01 million in 2009. Even the average price per square foot rose in 2010, hitting $1,203, up 8.3% from an average price of $1,111 in 2009. The sales price increase was due to a gain in market share of higher priced single-family townhouses over lower priced three- to five-family townhouses.

Single-family townhouses accounted for 51% of sales in 2010, up from 42% the previous year, while the market share of three- to five-family townhouses fell to 22% in 2010 from 30% the previous year. This is the highest market share for single-family townhouse sales in 11 years. In 1999, that share was 58%, but it has hovered around the mid- to high-30s in the last decade.

“There’s a tremendous premium for single-family properties,” said Jonathan Miller, chief executive of Miller Samuel. He attributed the increase in their share of the market to the relative strength of their rebound in 2010.

“Three- to five-family properties recovered in 2009,” he said. “But one-family properties took the baton last year.”

Prices rose in most of the Manhattan markets, except downtown. There the average sales price fell 18% last year to $5.27 million and the average price per square foot fell 10.2% to $1,335. Mr. Miller attributed the drop to fewer single-family townhouses in that part of the borough.

At 1.9%, the townhouse market remained a tiny share of the overall residential sales in 2010.