The labor force participation rate is the percentage of adults who have a job, or who are looking for one. In the U.S., about 75% of women ages 25 to 54 participate in the workforce. That's less than men of the same age, who come in at 90%. Still, the number is a big improvement over the early 70s, when fewer than half of women were in the labor force.
The rate climbed for decades, but right around 2000, it began to level off. That didn't happen in many other countries and today, the U.S. has one of the lower female labor force participation rates of the advanced economies, behind Denmark, the U.K., Canada and Australia.