NEW YORK - January 12, 2010 - Even when the U.S. labor market finally starts adding more workers than it loses, many of the unemployed will find that the types of jobs they once had simply don't exist anymore.

The downturn that started in December 2007 delivered a body blow to U.S. workers. In two years, the economy shed 7.2 million jobs, pushing the jobless rate from 5% to 10%, according to the Labor Department. The severity of the Depression is reshaping the labor market. Some lost jobs will come back. But some are gone forever, going the way of typewriter repairmen and streetcar operators.

Many of the jobs created by the booms in the housing and credit markets, for example, have likely been permanently erased by the subsequent bust.

"The tremendous amount of economic activity associated with housing, I can't see that coming back," says Harvard University economist Lawrence Katz. "That was a very unhealthy part of the economy."