Nearly one in four babies are born to unmarried couples who are living together, a new Centers for Disease Control survey found.

About 23 percent of the reported births were to unmarried heterosexual couples who were living together when their child was born -- up from 14 percent in 2002.

The government previously said more than 40 percent of births are to unwed mothers, but the latest study shows most unwed births occur in cohabiting couples.

The CDC interviewed more then 22,000 men and women from 2006 to 2010.