The number of women in the workplace has been declining for several years and experts had theorized that more women were deciding to forego careers and be stay-at-home moms.
But a Congressional study released today found that women aren't "opting out" of the workforce to raise children. For the first time in nearly a half-century, they are being forced onto the sideline by bad economic times.
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The number of women entering the workforce had increased steadily since the 1960s, spurred on by the women's rights movement and a booming economy. The percentage of women with jobs peaked in 2000 at 75 percent.
While there have been slight dips in the number of working women in the past five decades, those numbers have always bounced back even stronger than before. But since 2000, the percentage of women finding jobs has remained below that 75 percent peak. As of June 2008, it stood at 73 percent.
"It's really highly remarkable that the progress of having more women coming into the labor force evaporated in this past decade," said Lawrence Mishel, president of Economic Policy Institute.
That may seem like a small number, but those 2 percentage points represent about 4 million women who are not employed.
Tootie Samson of Baxter, Iowa, was laid off nine months ago from her job on the assembly line at Maytag.
"I enjoyed the life there and the people that I worked with, and I enjoyed working on a new product," said the 48-year-old mother.
She's spent countless hours looking for a new job, but the amount of money she's being offered doesn't compare to what she was earning.
"Most of them pay $8, $9. At Maytag our base pay was $20 an hour, plus we got incentives," Samson said.
A drop in pay is a big reason more women in their prime earning years, between 25 and 54, are leaving the workplace, the study said.
"The economy is an equal opportunity offender," said Marisa Thalberg, founder and president of Executive Moms. "If anything, this study should debunk the notion that women go out the workforce just to raise children. It's not a pure emotional decision [to leave the workforce.] For many women, there's as much pressure as any man would feel to be a breadwinner."
Median pay for women has gone from $15.04 in 2004 to $14.84 today, according to the Economic Policy Institute.
More women have left manufacturing jobs than any other sector, but the Congressional report found that women across the spectrum – whether white-collar, blue-collar, single, married, black or white – have been affected.
Women on average bring home about one third of the family income, so their defection from the workplace could have a devastating effect on the economy down the road.
Tootie Samson and others like her are worrying about the here and now.
"I still have a child at home and have to look into that in four years she will be looking at going to college, and with the price of everything going up, it's very hard," she said.
What Does It Mean to You?
"GMA" workplace contributor Tory Johnson answers some frequently asked questions about the congressional report's findings.
How big of a difference is this?
It's an enormous difference.
It erases more than 12 years of gains in terms of women joining the workforce. That translates into 4 million more women in their prime earning years who would normally be in the workforce now, but are not.
We've been hearing for the past few years that women were "opting out," choosing to stay home to raise their kids. But this new research shows that's simply not true. Women have dropped out for gender-neutral reasons: an economic downturn that brought layoffs, outsourcing and even pay cuts, which has made the decision to drop out a fairly straightforward one for many women. And it has nothing to do with motherhood.
Is there a pattern based on level of education, race or marital status?
No. This study finds that the trend is across the board for women: white collar/blue collar; single/married; black/white; with teens or with toddlers. Everyone is affected.
What effect does this have on the family?
It's not good at all. Women are no longer able to act as a financial safety net. Women typically bring home a third of their family's income, and of course single mothers are the sole breadwinners in their households. So this leaves those families very vulnerable.
And, in past recessions, when a woman was not working and her husband lost his job, she could go out and get a job to fill the gap. But that is no longer the case now that women are experiencing job losses as steeply as men.
What is the single most important thing to do for women who want to get back into the workforce?
Retraining. More than 1 million women have lost manufacturing jobs since 2001. These women found that jobs available to them paid less, so many of them said forget it. If they want to get back to work in a different field and at a higher wage, they need more education and new skills.
ABC News' Lisa Stark contributed to this report.