Cohabitation has become a normal state for American couples, either preceding marriage, following a breakup, or, in a smaller number of cases, replacing marriage. In 1960, only 400,000 couples in the U.S. cohabited, but by 2013 that had risen to 8 million couples, according to ISR researcher Pamela Smock. Of those cohabiting couples, 50 percent will eventually marry, 40 percent will break up, and 10 percent will cohabit for a longer period, Smock told Fox Business News in a May 16 interview. Still, while the majority of couples now live together outside marriage at some point in their lives, Smock said, cohabitation plays a different function for different people. “The role of cohabitation in our lives depends on what social class one is from,” she said. “The more privileged people are meeting, dating, and cohabiting, then marrying, with a wedding, and having children.” Those with less money and education are more likely to cohabit without marriage and to have children before marriage. Of the 41 percent of births now occurring out of wedlock, 60 percent are to cohabiting couples, Smock said.