For the first time since the end of World War II, the economic fortunes of American families have fallen across all levels, a nationwide survey indicates. The past 10 years have been the most brutal for people who consider themselves middle class, the Pew Research Center reported. In a report titled \"The Lost Decade of the Middle Class,\" Pew said an overwhelming majority of middle class adults reported it\'s much harder now to maintain their standard of living. They think they know who\'s to blame, too. Of the nationally representative 1,287 adults surveyed, 62 percent put \"a lot\" of the blame on Congress while 54 percent pointed the finger at banks and financial institutions and 47 percent said large corporations. The Bush administration was blamed by 44 percent of those asked while only 34 percent blamed the Obama administration. The middle class itself has shrunk, Pew said, with its members either moving up to higher income levels or falling back. In 2011, 51 percent of adults were middle class, a drop of 10 percent from 40 years ago. Upper-income families rose to 20 percent of adults, a 6-point increase from 1971. Lower-income families grew to 29 percent from 25 percent. Four in 10 middle class adults, 42 percent, said they were in worse financial shape than before the recession while 32 percent said they were better off. While the media income of middle class families fell 5 percent, their wealth as measured by assets minus debt slumped 28 percent, from $129,582 to $93,150. At the same time, the median wealth of upper income families rose 1 percent. Those surveyed said a second-term President Obama would do a better job at helping the middle class than his Republican opponent Mitt Romney, 52 percent versus 42 percent. Romney\'s policies would help the wealthy more, 71 percent of the middle respondents said, while 62 percent said Obama\'s policies would help the poor more. Middle class families are defined as those living in households with an annual income that is 67 percent to 200 percent of the national median. The survey was conducted July 16-26 and has a margin of error of 2.8 percentage points.