Womens History Month Facts, U.S. Department of the Census
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 in 2011. The number of males was 153.3 million.
Source: Population Estimates: 2011, Table NC_EST2011_01
At 65 and older, there were 13.3 percent more women than men in 2011. Source: Population Estimates: 2011, Table NC_EST2011_01
For more census facts about women: http://www.census.gov/newsroom/releases/archives/facts_for_features_special_editions/cb13-ff04.html
Women in Military Service: http://www.defense.gov/home/features/2012/0212_womenshistory/