By Erika Morphy | GlobeSt.com WASHINGTON DC-Condo sales in the area are on the rise after a two year trough according to a new study by Delta Associates and McWilliams\Ballard. New-unit sales volume defined as net binding contracts written with security deposits registered 686 units in Q3 in the area -- the highest quarterly sales volume in two years. Also in the past 12 months there were 2 120 sales an increase of 45% from the prior 12-month period.