Most Out-of-Wedlock Births are In-Cohabiting-Union

Among the nearly 4 million babies born in 2013, a substantial 40.6 percent were born to a single mother, according to the National Center for Health Statistics. This figure has barely changed despite the 14 percent decline in the birth rate of unmarried women since 2007.

A closer look at the nation's "single" mothers, based on 2006-10 data from the National Survey of Family Growth, reveals that most are not single at all. The 58 percent majority are in a cohabiting union, according to NCHS.

Source: National Center for Health Statistics, Recent Declines in Nonmarital Childbearing in the United States