Estimated number of mothers of all ages in the United States: 80.5 million

Percentage of women 40 to 44 years old who are mothers: 81%

Approximate number of women who give birth each year in the United States: 4 million. Of this number, about 415,000 are age 15 to 19, and more than 100,000 new moms are age 40 or older.

Average age of women when they give birth for the first time: 25.2 (a record high)

Average number of children that U.S. women today can expect to have in their lifetime: 2.0

Number of stay-at-home moms, in 2004: 5.6 million

Number of stay-at-home dads: 143,000

Among mothers of infants, percentage in the labor force: 55%

The percentage of women who gave birth to their first child and returned to work within four months: 51%

Percentage of mothers, ages 15 to 44, whose oldest child is age 3-5, in the labor force: 67%  

Percentage of mothers, with children age 5 and under, employed full-time, year round: 33%

Percentage of mothers, ages 15 to 44, whose youngest child is 12 or older, in the labor force: 80%

Number of single mothers living with children under 18: 10 million

http://www.now.org/issues/mothers/facts.html