Divorce in US plunges to 35-year low

Meanwhile, marriage is up a bit, at 32.3 marriages for every 1,000 unmarried women age 15 or older last year, from 31.9 in 2014. It was the highest since 2009, suggesting that, after a plunge of several decades, matrimony could be stabilizing.

"The decline has stopped," said Wendy Manning, co-director of the National Center for Family & Marriage Research at Bowling Green State University.

Every year, the center uses census data to calculate the previous year's marriage and divorce trends. This year's calculations show that divorce has been dropping quickly, to a rate of 16.9, down from 17.6 in 2014 and a peak of almost 23 in 1980.

It's hard to know exactly why divorce is in decline. Factors could include the aging of the U.S. population, changing gender roles, and the fact that there are fewer marriages to break up in the first place.

And unfortunately, the decline in year-to-year divorce statistics doesn't necessarily mean any particular marriage is more likely to last.

Baby boomers, for example, married young and have continued marrying and divorcing even at older ages, while it isn't clear yet whether millennials and Generation X will follow suit.

Look at the marriage rate. One reason it has fallen so steeply over the decades is that these younger generations have pushed getting married further into adulthood. Many sociologists believe the typical marriage today still has about a 50/50 probability of lasting, the same chance it had decades ago.

"We've seen a decline of divorce among people who are younger and an increase among people who are older," Manning said.

Is there any such thing as a typical marriage? Divorce and marriage rates vary widely among different segments of the population. Washington, D.C., and Wyoming had divorce rates last year of 29.9 and 27.9, the highest in the country. Next came Nevada, Arkansas, and Alaska. The lowest divorce rates were in Hawaii, at 11.1, followed by Wisconsin, Rhode Island, Delaware, and New Jersey, all under 13.

The northeastern U.S. has the lowest marriage rates, and Utah, not surprisingly, the highest. At 61.3, Utah's marriage rate is nearly three times Rhode Island's of 21.4. But here's a surprise: Utah's divorce rate is about 18, higher than in 40 percent of the states. Well, it's a lot of marriages to roll the dice on.

Marriage has been holding steady for the past several years, but weddings are still half as common as they were in the 1970s and early 1980s. What are Americans doing instead? Some are staying single and living alone, but many couples are doing what used to be called living in sin, sharing a home without officially tying the knot.