Couples who live together before they get married are less likely to stay married, a new study has found.  The likelihood that a marriage would last for a decade or more decreased by six percentage points if the couple had cohabited first, the study found.

The study of men and women ages 15 to 44 was done by the National Center for Health Statistics using data from the National Survey of Family Growth conducted in 2002. The authors define cohabitation as people who live with a sexual partner of the opposite sex.

“From the perspective of many young adults, marrying without living together first seems quite foolish,” said Prof. Pamela J. Smock, a research professor at the Population Studies Center at the University of Michigan, Ann Arbor. In general, one in five marriages will dissolve within five years. One in three will last less than 10 years. Those figures varied by race, ethnicity and sex.