U.S. homes are expected to lose more than $1.7 trillion in value during 2010, which is 63 percent more than the $1 trillion lost in 2009, according to analysis of recent Zillow Real Estate Market Reports. That brings the total value lost since the market peaked in June 2006 to $9 trillion. By comparison, from 2001 to the end of September 2010, the war in Iraq has cost $750.8 billion, according to a September report by the Congressional Research Service. The bulk of the total value lost during 2010 was in the second half of the year. From January to June, the housing market lost $680 billion. From June to December, Zillow projects residential home value losses will top $1 trillion. Less than one-fourth of the 129 markets tracked by Zillow showed gains in total home values during 2010. Among those were the Boston metropolitan statistical area, which gained $10.8 billion in value, and the San Diego MSA, which gained $10.2 billion. Declines in home values have led to increases in the percentage of homeowners in negative equity. At the end of 2009, 21.8 percent of single-family homeowners with mortgages were in negative equity, meaning they owed more on their mortgage than their home was worth. In the third quarter of 2010 – the last time Zillow calculated negative equity – 23.2 percent were underwater.