WASHINGTON – U.S. divorces are leveling off after decades of increases, with couples now slightly more likely to reach their 10-year wedding anniversary. But the “seven-year itch” among couples persists, with nearly one out of two first marriages estimated to end in divorce.

Roughly 75 percent of those who have married since 1990 reported they had reached their 10-year anniversary. That’s up about 3 percentage points for both men and women who married a decade earlier in the 1980s, when divorce rates in the United States had peaked, according to census figures released Wednesday.

The census report partly attributed the small declines in divorce to a recent jump in couples cohabitating, as well as rising median ages before marriage as people wait longer before making long-term commitments. Increases in educational attainment and job opportunity might also be a factor.

“There’s a new marriage bargain based on having two earners that seems to be working for more and more couples,” said Andrew Cherlin, a sociology professor at Johns Hopkins University, citing a stronger economic basis for couples to stay together and raise a family. “Most divorces have always occurred within 10 years of marriage because most people who are unhappily married figure that out quickly.”

Divorces climbed mostly sharply in the late 1960s and 1970s, amid the passage of laws that made dissolving marriages quicker and easier.

The report found that couples who broke up on average separated upon roughly seven years of marriage, a phenomenon often referred to as the “seven-year itch,” before divorcing a year later. For those who remarried, they typically waited nearly four years.

The 2009 numbers are based on the Census Bureau’s Survey of Income and Program Participation, which samples 55,497 adults who have ever been married.