The following graph shows the number of cities with increasing house prices on a year-over-year and month-over-month basis. This graph is based on the Case-Shiller Composite 20 cities using seasonally adjusted data starting in January 2001.

Most cities were seeing month-over-month increases every month through 2005. In 2006, some cities started seeing year-over-year declines (red). There were still a few cities with increasing prices in early 2007. The increases in 2009 and 2010 were related to the housing tax credit (all of those gains and more are gone).