WASHINGTON – Interracial marriages in the U.S. have climbed to 4.8 million – a record 1 in 12 – as a steady flow of new Asian and Hispanic immigrants expands the pool of prospective spouses. Blacks are now substantially more likely than before to marry whites.

A Pew Research Center study, released today, details a diversifying America where interracial unions and the mixed-race children they produce are challenging typical notions of race.

“The rise in interracial marriage indicates that race relations have improved over the past quarter century,” said Daniel Lichter, a sociology professor at Cornell University.

“Mixed-race children have blurred America’s color line. They often interact with others on either side of the racial divide and frequently serve as brokers between friends and family members of different racial backgrounds,” he said. “But America still has a long way to go.”

The figures come from previous censuses as well as the 2008-2010 American Community Survey, which surveys 3 million households annually. The figures for “white” refer to those whites who are not of Hispanic ethnicity.

The study finds that 8.4 percent of all current U.S. marriages are interracial, up from 3.2 percent in 1980. While Hispanics and Asians remained the most likely, as in previous decades, to marry someone of a different race, the biggest jump in share since 2008 occurred among blacks, who historically have been the most segregated.

States in the West where Asian and Hispanic immigrants are more numerous, including Hawaii, New Mexico and California, were among the most likely to have couples who “marry out.” By state, mostly white Vermont had the lowest rate of intermarriage, at 4 percent.

In all, more than 15 percent of new marriages in 2010 were interracial.

About 83 percent of Americans say it is “all right for blacks and whites to date each other,” up from 48 percent in 1987.