Which helps explain why there were just 36,000 U.S. operators in 2010, down nearly two-thirds in 10 years.

A job that rose in the same period? Software engineer. They numbered 1.03 million in 2010, up nearly 40 percent.

____

AP researcher Judith Ausuebel in New York contributed to this story. You can reach Bernard Condon on Twitter at http://twitter.com/BernardFCondon

Copyright 2011 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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