There were 6,586 closed residential transactions in Westchester County and 646 in Putnam County during 2010, according to the Westchester Putnam Association of Realtors’ fourth-quarter report, released today. The total dollar volume of sales in both counties was $4.3 billion in 2010, compared to $3.5 billion in 2009. That activity resulted in a 13 percent increase in sales since 2009 in Westchester County, and just a .5 percent increase in sales in Putnam County, compared to 2009. The single-family housing sector in both counties did the best, with Westchester’s 4,014 house sales seeing a nearly 20 percent increase over 2009’s sales, and Putnam County’s 576 house sales increasing by close to 6 percent over 2009. Condominium sales in Westchester picked up their pace, too, with a 14 percent increase over 2009. In Putnam County, however, condominium sales decreased by 28 percent from 2009. TRD