The rate peaked at 67.3 percent in early 2000 after women had poured into the work force over the previous four decades. Since then, it's turned south. Demographic and social trends help explain the drop: Baby boomers are aging and retiring.
And more women, especially in upper-income families, are staying at home. The drop in the participation rate accelerated after the economy slid into recession in late 2007. The tough job market led many to give up looking for work.
The stock market didn't take Friday's news well.
The Dow Jones industrial average closed down 168 points, or about 1.3 percent. The broader Standard & Poor's 500 index sank 1.6 percent.
Investors were a lot happier earlier this week, when they sent the Dow to its highest close since December 2007.
Technology stocks and banks led the market lower Friday. Utility companies were the only broad category of stock in the S&P 500 index trading higher. They tend to fare well when investors grow nervous about the economy.
Investors flocked to the safety of U.S. government bonds. The yield on the benchmark 10-year Treasury note dropped to 1.88 percent, its lowest point since February, from 1.92 percent late Thursday.
NOT EXPLOSIVE, BUT STEADY
By some measures, job creation has been consistently solid. For example, more than 100,000 jobs have been added for eight straight months. It's the first time the economy has achieved that feat since 2005.
Consider, too: Employers have added at least 100,000 jobs every month this year. That would be an impressive streak if it continues through 2012. The last time the economy added 100,000 or more jobs every month in a calendar year was 1999.
Associated Press writers Martin Crutsinger and Kasie Hunt contributed to this report.
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.