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.

The number of females in the United States according to the 2010 Census is 157 million. The number of males was 151.8 million. At 85 and older, there were more than twice as many women as men.

The estimated number of mothers in the United States in 2009 was 85.4 million.

The median annual earnings of women 15 or older who worked year-round, full time, in 2010, was $36,931 – the same as it was in 2009.

The umber of women 25 and older with a bachelor’s degree or higher in 2010 was 30.7 million. This compares to 29.2 million men.

Women had a larger share of high school diplomas (including equivalents), as well as associate, bachelor’s and master’s degrees. More men than women had a professional or doctoral degree.

Revenue for women-owned businesses in 2007 was $1.2 trillion. In that year, there were 7.8 million women-owned businesses.