National Women’s History Month’s roots go back to March 8, 1857, when women from New York City factories staged a protest over working conditions. International Women’s Day was first observed in 1909, but it wasn’t until 1981 that Congress established National Women’s History Week to be commemorated the second week of March. In 1987, Congress expanded the week to a month. Every year since, Congress has passed a resolution for Women’s History Month, and the President has issued a proclamation. Following are a few key statistics on women in the United States and the role they play in our labor force and economy.

161 million 

The number of females in the U.S. as of December 2013. The number of males was 156.1 million. 

75.1 million

The number of females 16 and older who participated in the civilian labor force in 2013. Women comprised 47.4 percent of the civilian labor force in 2013.

63% 

Percentage of social scientists who were women, the heaviest representation of women among all STEM (science, technology, engineering and math) fields. Among other STEM fields, approximately 14 percent of engineers, 45 percent of mathematicians and statisticians and 47 percent of life scientists were women.

$39,157

The median annual earnings of women 15 or older who worked year-round, full time in 2013. In comparison, the median annual earnings of men were $50,033.

1.6 million

Number of women veterans in the United States in 2013.

For more interesting statistics on women in the United States, please go to the latest issue of the U.S. Census Bureau's Facts for Features.