The number of housing units sold in the DC area in September 2007, has dropped precipitously from September of last year. The number of sold single family houses fell 42.2% from September 2006 and 67% from September 2005 in Montgomery County, MD. In DC, the percentage decline was basically the same, at 42.1%. The months supply of single family houses in Montgomery County, MD for September 2007 has now reached over 10 months. There were 4520 active listings and only 423 single family houses sold.