The Mother's Day holiday celebrates its 100th anniversary this year. The U.S. Census Bureau provides the following numbers about moms in the U.S.:

• 55 percent of mothers are between the ages of 15 and 44.

• 81 percent of women between the ages of 40 and 44 are mothers. In 1976, 90 percent of women in that age group were mothers.

• 94.1 births per 1,000 reflects the number of births in Utah in 2006, the nation's highest. Vermont was the lowest with 52.2. West Virginia's was 58.3

• 10.4 million single mothers live with children younger than 18, up from 3.4 million in 1970.

• 83 percent of mothers who went back to work within a year of their child's birth returned to the same employer.

• 5.6 million is the number of stay-at-home moms in 2006.