WASHINGTON (CBSDC) - Health officials say nearly 1 in 4 babies are born to unmarried couples that are living together, which is a significant jump form a decade ago.

The government previously said more than 40 percent of births are to unwed mothers. However, a report released Thursday offers new detail, showing most unwed births occur in cohabiting couples.

The information is based off a study by the Centers for Disease Control and Prevention in which more than 22,000 men and women were interviewed face-to-face between 2006 and 2010.

About 23 percent of the reported births were to unmarried heterosexual couples who were living together when the child was born, which was up from 14 percent when a similar study was conducted in 2002.

The CDC did not speculate on reasons for the increase.