The number of residences sold in the Baltimore metropolitan area dropped in 2010 from the prior year, according to RealEstate Business Intelligence LLC, or RBI, a source of real estate information in the mid-Atlantic region. Last year, 23,033 units were sold, 2.8 percent fewer than the 23,693 sold in 2009. Still, the 2010 figure was 1.4 percent above the 22,719 units sold in 2008, RBI reported. Among other findings: Cash purchases of homes increased in 2010 due to restricted lending; for-sale homes were on the market an average of 108 days, nearly two weeks less than the 121-day average of the previous two years. For the full monthly data report, go to www.rbintel.com/statistics.