WASHINGTON — The U.S. middle class has shrunk drastically over the last 10 years as Americans' net worth has plunged, wages declined, and standards of living slipped away, according to a study released Wednesday by the Pew Research Center.
The study also highlights diminished hopes among the roughly 50 percent of adults defined as middle class, with household incomes ranging from $39,000 to $118,000.
The report describes this midtier group as suffering its "worst decade in modern history," having fallen backward in income for the first time since the end of World War II.
Three years after the recession technically ended, middle class Americans are still feeling the economic pinch, with most saying they have been forced to reduce spending in the last year.
Fewer now believe that hard work will allow them to get ahead. Families are more likely to say their children's economic future will be the same as or worse than their own. In all, 85 percent of middle-class Americans say it is more difficult now than a decade ago to maintain their standard of living.
Middle-income earners place the blame for their plight on U.S. lawmakers, banks, and big business, the findings by the Pew Research Center showed.
"There's been a very steady, long-term shrinkage" in the number of people in the middle class, said Paul Taylor, executive vice president for the nonpartisan research group. "There's also less money in the middle."
Since 2001, median household income has fallen to $69,487 in 2010 from $72,956, the report said.
The median household net worth, which is the value of assets minus debt, dropped to $93,150 from $129,582 over the same 10-year period, according to Pew.
Among upper-income families, net worth edged higher, to $574,000 from $569,000.
Lower-income families saw net worth fall 45 percent to $10,000.
The Pew center's report was issued amid a presidential campaign that has become in part a referendum on whether President Obama's policies have helped Americans as the nation struggles to recover from deep economic woes.
Republican rival Mitt Romney, a multimillionaire former private equity executive, has based his campaign on his pledge to add jobs and improve the economy.
Pew's survey found more of the middle class support Mr. Obama's policies than Mr. Romney's.
That may not be surprising given that the poll also found half the middle class adults polled leaned Democratic, while 39 percent said they identified more with Republicans. Eleven percent said they were not drawn to either political party.
The plight of the middle class has become a bellwether of the U.S. economy in the wake of the recent Great Recession that officially ran from December, 2007, to June, 2009, ending just six months into Mr. Obama's term.
According to the poll, 62 percent of respondents said Congress deserved "a lot" of the blame for the nation's economic troubles over the last decade, while 29 percent blamed lawmakers "a little."
Banks and financial institutions as well as large corporations were also largely at fault, respondents told Pew.
Just 8 percent blame the middle class itself.
Various surveys have shown Americans — particularly women, minorities, children, and young adults — are still struggling amid the slowest economic recovery since the 1980-81 period.
The shifting middle class over the last decade is just part of a longer trend, Pew researchers said.
About 50 percent of U.S. adults fell into the middle class in 2011 compared to 61 percent in 1971, as more Americans either moved into upper or lower income groups, the center said.
Over time, the wealthy have also seen their share of total U.S. household income rise, it found. Upper income earners held 46 percent of the nation's household income in 2010, compared with 29 percent in 1970.
In comparison, the middle class' share of income fell to 45 percent from 62 percent over the same period, and lower income earners' share stayed flat at about 10 percent.
"The job market is changing, our living standards are falling in the middle, and middle-income parents are now afraid that their children will be worse off than they are," says Timothy Smeeding, a University of Wisconsin-Madison economics professor who specializes in income inequality.
He said many middle-income families have been hit in the last decade as health-care costs increase, mid-wage jobs disappear because of automation and outsourcing, and college tuition mounts for those seeking to build credentials to get better work.
In the meantime, more-affluent families have fared better in net worth because they are less dependent than lower-income groups on home property values, which remain shriveled after the housing bust. Wealthier Americans are more likely to be invested in the stock market, which as a whole has been quicker to recover from the downturn.
The Pew survey involved telephone interviews with 2,508 adults, including 1,287 people who identified themselves as middle class, conducted from July 16 to 26. The margin of error was 2.8 percentage points for the total sample, 3.9 percentage points for those in the middle class.
First Published August 23, 2012, 12:44 p.m.