LOS ANGELES – When it comes to saying “I do,” more and more Americans seem to really mean, “Not so much,” according to a new analysis of the increasingly troubled institution of marriage.

Just over half of all adult Americans, 51 percent, are currently married, according to an analysis of U.S. Census data by the Pew Research Center. The center predicts that, if current trends continue, the share of currently married adults will fall below half within a few years. In 1960, 72 percent of all adults 18 and older were married.

The analysis shows that, though the traditional marriage is giving way, other lifestyle forms – including cohabitation, single-person households and single parenthood – are growing.

Interestingly, the United States is not alone in moving away from the institution of marriage, according to the survey.

“The same trend has taken hold in most other advanced post-industrial societies, and these long-term declines appear to be largely unrelated to the business cycle. The declines have persisted through good economic times and bad,” notes the report, released Wednesday.

As is usually the case, it is the young who are leading the way. Just one in five, 20 percent, of adults 18 to 29 are married, compared to 59 percent in 1960.

The young are also waiting to marry, the analysis found. In the past half century, the median age for first marriage has risen by about six years for both sexes, with grooms marrying at 28.7 years and brides at 26.5 years.