International Women's Day was first observed in 1909.

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.

154.7 million
The number of females in the United States as of Oct. 1, 2008. The number of males was 150.6 million. At 85 and older, there were more than twice as many women as men.

82.8 million
Estimated number of mothers of all ages in the United States.

1.9
Average number of children that women 40 to 44 had given birth to as of 2006, down from 3.1 children in 1976, the year the Census Bureau began collecting such data. The percentage of women in this age group who were mothers was 80 percent in 2006, down from 90 percent in 1976.

$34,278
The median annual earnings of women 16 or older who worked year-round, full time, in 2007, up from $33,648 in 2006 (after adjusting for inflation). Women earned 77.5 cents for every $1 earned by men.

$49,364
Median earnings of women in 2007 in the District of Columbia, a total not statistically different from the men. In all of the 50 states, women had lower earnings than the men. The District of Columbia, Connecticut, Massachusetts, Maryland and New Jersey were the only states or equivalents where median earnings for women were greater than $40,000.

$61,957
Median earnings of women working in computer and mathematical jobs, the highest among the 26 major occupational groups. In the installation, maintenance and repair occupations and community and social services group, women's earnings as a percentage of men's earnings were higher than 90 percent.

33%
Percent of women 25 to 29 who had attained a bachelor's degree or higher in 2007, which exceeded that of men in this age range (26 percent).

28.2 million
Number of women 25 and older with a bachelor's degree or more education in 2007, more than double the number 20 years earlier.

28%
Percent of women 25 and older who had obtained a bachelor's degree or more as of 2007. This rate was up 11 percentage points from 20 years earlier.

928,000
The projected number of bachelor's degrees that will be awarded to women in the 2008-09 school year. Women are also projected to earn 391,000 master's degrees during this period. Women would, therefore, earn 58 percent of the bachelor's and 60 percent of the master's degrees awarded during this school year. In addition, women would earn nearly 50 percent of first-professional degrees, such as law and medical.

More than $939 billion
Revenue for women-owned businesses in 2002. There were 116,985 women-owned businesses with receipts of $1 million or more.

Nearly 6.5 million
The number of women-owned businesses in 2002. Women owned 28 percent of all nonfarm businesses.

More than 7.1 million
Number of people employed by women-owned businesses. There were 7,231 women-owned businesses with 100 or more employees, generating $274 billion in gross receipts.

13%
Percentage of women-owned businesses in California, which had the most women-owned businesses at 870,496. New York was second with 505,077 or 8 percent of all businesses. Texas was third in number of businesses with 468,705, accounting for 7 percent of all businesses.

65%
Percentage of female citizens 18 and older who reported voting in the 2004 presidential election. Sixty-two percent of their male counterparts cast a ballot.

49%
Percentage of female citizens who voted in the 2006 congressional elections, compared with 47 percent of men.

59%
In 2007, the percentage of females 16 and older who participated in the labor force, representing about 71 million women. The participation rate for males in this age category was 73 percent.

38%
Percent of females 16 or older who worked in management, professional and related occupations, compared with 32 percent of males.

22.5 million
Number of female workers in educational services, health care and social assistance industries. More women worked in this industry group than in any other. Within this industry group, 11.2 million worked in the health care industry and 8.6 million in educational services.

94,000
Number of female police officers across the country in 2007. In addition, there were about 14,000 women firefighters, 330,000 lawyers, 266,000 physicians and surgeons, and 36,000 pilots. (Note: Number of pilots pertains to 2006.)

198,400
Total number of active duty women in the military, as of Sept. 30, 2007. Of that total, 33,500 women were officers, and 164,900 were enlisted.

14%
Proportion of members of the armed forces who were women, as of Sept. 30, 2007. In 1950, women comprised less than 2 percent.

1.8 million
The number of military veterans who were women in 2007.

62.6 million
Number of married women (including those who were separated or had an absent spouse) in 2007. There were 60.7 million unmarried (widowed, divorced or never married) women.

18%
Percentage of married couples in which the wife earned at least $5,000 more than the husband in 2007.

23%
Percentage of married couples in which the wife had more education than the husband in 2007.

5.6 million
Number of stay-at-home mothers nationwide in 2007, up from 4.6 million a decade earlier.