By Blake Ellis, staff reporter

NEW YORK (CNNMoney.com) -- Can't sell your home for a decent price? You're not alone.

American homes are expected to be worth $1.7 trillion less in 2010 than they were worth last year, according to a report released Thursday by real estate website Zillow.

This year's drop in home values is 63% bigger than the $1 trillion dip in 2009, and brings the total value lost since the housing market's peak in 2006 to a whopping $9 trillion.

While the homebuyer tax credit helped prop up the housing market in the second half of 2009 and the first half of 2010, home values continued their slide in the second half of the year. Almost $700 billion in value was lost in the first half of

"It's a testament to the nearly irresistible force of the overall market correction that government incentives can only temporarily hold back the tide, and that the market will ultimately find its natural equilibrium of supply and demand," said Zillow Chief Economist Dr. Stan Humphries.

And it may not get much better.

"Unfortunately, with foreclosures near an all-time high in late 2010 and high rates of negative equity persisting, it does not appear that the first part of 2011 will bring much relief," Humphries said.

Only 24% of the 129 markets Zillow tracked increased in total home value this year. Home values increased $10.8 billion in the Boston metropolitan statistical area (MSA), and $10.2 billion in San Diego MSA.

The areas suffering the biggest drops in home prices include New York City, which lost $103.7 billion in value and Los Angeles, where home values fell $38.6 billion.

The steep declines in home values are pushing Americans further under water every year. In the third quarter of 2010, 23.2% of single family homeowners with mortgages owed more on their mortgage than their home was worth -- up from 21.8% in 2009. 

the year, compared to Zillow's estimates of $1 trillion in the second half of 2010.