NEW YORK -- The US divorce rate has dropped to its lowest since 1970, as people wed later in life, live together without marrying, and secure prenuptial agreements, particularly among the affluent.

The rate, which measures the number of divorces against the total population, peaked at 5.3 per 1,000 people in 1981 and settled at 3.6 in the 12 months prior to September 2006, the most recent data available, according to a May 4 report by US health officials.

The marriage rate also dropped to 7.3 in 2005 from 7.6 the year earlier and 7.7 in 2004, the report said. People are taking longer to decide who they'll marry and more are considering financial security, whether to have children, and which religion to belong to before tying the knot, according to lawyers who specialize in matrimonial law and sociologists.

"People are just more savvy going in about the likelihood of divorce," said Marina Tucker, a matrimonial attorney at Feldesman Tucker Leifer Fidell LLP in Washington, in a telephone interview. Once married, they're "more willing to seek marriage counseling as a way to mediate issues," she said.

Tucker said she "definitely" sees fewer divorces in marriages that have hammered out prenuptial legal agreements. Lawyers tell their clients ahead of time "all the terrible things that might happen in the future," she said. "It makes them think everything through."

The divorce and marriage data was prepared by the US Centers for Disease Control and Prevention's National Center for Health Statistics. Of the states reporting, Florida had the most divorces with 66,712 from January to September 2006. Texas was second with 60,195 and New York was third at 38,422.

There is no divorce data from several states that declined to supply their information, including California. That state did supply data on marriages, leading the country with 167,173 nuptials during the same period, followed by Florida with 121,479 and Texas with 132,394.

Andrew J. Cherlin, a professor of public policy in the sociology department at Johns Hopkins University in Baltimore, said the divorce rate has been falling off strongly among the college-educated in America, even as it continues to creep up for the least schooled.

A number of studies have shown that more highly educated people tend to marry at an older age, and more of them live together without marrying.

"In a funny way, the postponing of marriage is lowering the divorce rate -- young couples live together without marrying, and when they break up the split doesn't count as a divorce," Cherlin said in a telephone interview.

Additionally, he said college-educated couples "have been the winners in our globalized economy -- they've gotten the better jobs, and their incomes are going up, so there's less strain on their marriages," Cherlin said.

Steven P. Martin, an assistant professor of sociology at the University of Maryland in College Park, Md., said that other factors may also be involved. For instance, he said there has been an increase in the proportion of marriages where there is a permanent breakup and no divorce, so there is no divorce certificate to count.

Also, recent research has shown that "fewer men and women are getting remarried if they separate," he said. "Thirty years ago, remarriage happened quickly."

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