The Sentier Research report, "Changes in Household Income During the Economic Recovery: June 2009 to June 2012," says the real median household income has fallen 4.8 percent since June 2009.
The recession officially lasted from December 2007 until June 2009. In those 18 months, the median household income fell 2.6 percent, which means the recovery – the 38 months since June 2009 -- has been more damaging to household incomes than the recession was.
That puts the median income 7.2 percent below December 2007, the report says.
The U.S. median income was $50,964 in June 2012, the study says.
Since January 2000, the start of the research group's statistical series, the real median annual household income has fallen 8.1 percent, dropping from $55,470 to $50,964, the study found.
"Based on our data, almost every group is worse off now than it was three years ago, with the exception of households with householders 65 years old and over," said Gordon Green of Sentier Research in a statement.
"For some groups of households -- blacks, men living alone, younger and upper-middle age brackets, those with some college but no degree, the unemployed, the self-employed, and those living in the West -- the declines tended to be larger than average," he said.