IStock Photo 4806103 © Juan Silva

According to the Bureau of Labor Statistics, the odds an employed person 16 or older is a member of a labor union are 1 in 8.04 (12.4 percent) compared to 20.1 percent in 1983. Those employed as educators and librarians have the highest unionization rate at 38.7 percent. The two largest teachers’ unions, the National Education Association (NEA) and the American Federation of Teachers (AFT), represent a combined 4.6 million members—more than a quarter of all unionized employees. The NEA, the largest trade union in the country, has 3.2 million members. The AFT has 1.4 million members.

Generally, the younger the worker, the less likely he or she will be unionized. The odds an employed person 16 - 24 is in a labor union are 1 in 20.11. The odds a worker 45 - 54 is in a union are 1 in 6.25; the odds for a worker 55 - 64 are 1 in 6.04.

Although the number of unionized workers as well as the percentage of unionized workers has decreased from 1983, there was a slight rise in union membership in 2008—to 12.4 percent, from 12.1 percent the year before. In November, 2009, the New York Times cited a study by the Center for Economic Policy Research, which found that manufacturing, once the stronghold of union membership, now represents only 11 percent of unionized workers.

In the auto industry, which has been hit hard by job losses and a weak economy, membership in the United Auto Workers (UAW) dropped below 500,000. Membership in the UAW was at its peak in 1979, when it boasted almost 1.5 million members. Since 2001, the union has lost more than a third of its membership.

The image of Hollywood’s defiant Norma Rae galvanizing her fellow factory workers into action feels especially dated today. With manufacturing jobs on the decline and more than half of the female unionized workforce in the public sector, today’s Norma Rae is more likely to be a middle-aged federal employee than a factory worker in her 20s.

According to the Center for an Economic Policy Research study, women now make up more than 45 percent of the unionized work force, and in the next decade will likely represent more than half of all union members. As with all workers, women between the ages of 55 and 64 are the most likely to be unionized. The odds a woman in that age group is in a union are 1 in 6.44; the odds a woman 16 - 24 is unionized are 1 in 24.51.

A 2009 study by UCLA's Institute for Research on Labor and Employment (IRLE) revealed that California, which has suffered from huge job losses and a poor economy, gained 131,206 union members between July 2008 and June 2009. Even as the country has seen unionization as a whole decrease, the percentage of the workforce that is unionized rose in California by 14 percent over the past two years.

“Usually with an economic downturn…unionization gets clobbered,” said Chris Tilly, the IRLE's director. “What we're having in this recession is a different story. Here is a horrific downturn, and the rate of unionization is increasing.”

The appeal of unionization, says the IRLE, “is easy to understand. In the United States today, average hourly earnings are about $4 more for union workers than non-union workers.”