There were 334,000 births among teenage girls aged 19 or younger in 2011, representing 8% of all U.S. births.[6] Births to teen mothers peaked in 1991 at 62 births per 1,000 girls. This rate was halved by 2011 when there were 31 births per 1,000 girls.[6] About 25% of teenage mothers have a second child within 24 months of the first birth.[13]