But 42 months after the Great Recession ended, the U.S. has gained only 3.5 million, or 47 percent, of the 7.5 million jobs that were lost. The 17 countries that use the euro had 3.5 million fewer jobs last June than in December 2007.

This has truly been a jobless recovery, and the lack of midpay jobs is almost entirely to blame.

Fifty percent of the U.S. jobs lost were in midpay industries, but Moody's Analytics, a research firm, says just 2 percent of the 3.5 million jobs gained are in that category. After the four previous recessions, at least 30 percent of jobs created â¿¿ and as many as 46 percent â¿¿ were in midpay industries.

Other studies that group jobs differently show a similar drop in middle-class work.

Some of the most startling studies have focused on midskill, midpay jobs that require tasks that follow well-defined procedures and are repeated throughout the day. Think travel agents, salespeople in stores, office assistants and back-office workers like benefits managers and payroll clerks, as well as machine operators and other factory jobs. An August 2012 paper by economists Henry Siu of the University of British Columbia and Nir Jaimovich of Duke University found these kinds of jobs comprise fewer than half of all jobs, yet accounted for nine of 10 of all losses in the Great Recession. And they have kept disappearing in the economic recovery.

Webb Wheel Products makes parts for truck brakes, which involves plenty of repetitive work. Its newest employee is the Doosan V550M, and it's a marvel. It can spin a 130-pound brake drum like a child's top, smooth its metal surface, then drill holes â¿¿ all without missing a beat. And it doesn't take vacations or "complain about anything," says Dwayne Ricketts, president of the Cullman, Ala., company.

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