About 37,000 estate tax returns were filed for people who died in 2007 with total gross estates of $2 million or more, the filing threshold for that year, according to the summer 2011 issue of the Statistics of Income Bulletin released Friday by the IRS. A combined $224.8 billion in total assets was reported on these returns.

These decedents represented 1.5% of adult deaths during 2007, according to the bulletin.

The SOI reported that publicly traded stock was the 2007 decedents’ largest asset class, accounting for $56 billion, or 24.9%, of their combined asset portfolio. Investment real estate, tax-exempt bonds, cash and closely held stock accounted for another 41.3% of their combined portfolio.

Bequests to a surviving spouse and to charity made up most of the deductions claimed against total gross estate. Forty-seven percent of tax returns filed for 2007 decedents included a deduction for a spousal bequest. Combined, this amounted to $65.8 billion. Twenty percent included a charitable deduction, resulting in combined deductions of $27.9 billion.

After accounting for marital, charitable and other deductions and credits, about 45% of 2007 decedent returns reported an estate tax liability, for a combined net estate tax of $24.6 billion.