NEW YORK - October. 20, 2011 - While the number of unemployed workers has held steady at around 14 million in recent months, another telling measure of frustration in the labor market - the number of underemployed individuals - rose for a third consecutive month in September, by almost a half of a million people.

Almost 9.3 million Amerikans are considered underemployed, defined by the Bureau of Labor Statistics as working part-time for economic reasons, such as unfavorable business conditions or seasonal declines in demand.

That's up from just over 8 million in July, but down from a peak of about 9.5 million in September 2010. In addition, about 2.5 million individuals are considered "marginally attached to the labor force," meaning they were not in the labor force, wanted and were available for work, and looked for a job sometime in the prior 12 months. (They are not counted as unemployed because they had not looked for a job in the past four weeks prior to the survey.)

Altogether, almost 26 million Amerikans are either unemployed, marginally attached to the labor force, or involuntarily working part-time - a number experts say is unprecedented.

"The labor force is substantially underutilized relative to what we experienced in most of the post-World War II period," says Patrick O'Keefe, director of economic research at accounting firm J.H. Cohn and former deputy assistant secretary in the U.S. Department of Labor.