Interracial marriages reached an all-time high in 2010, according to a study just released on Social and Demographic Trends project by the Pew Research Center.

“The upward trend of intermarriage is many decades old,” said Russ Oates of the Pew Center. “Marriage across racial and ethnic lines continues to be on the rise in the United States. Just as intermarriage has become more common, Americans’ growing acceptance of intermarriage is echoed on a personal level.”

The report tracks data from the U.S. Census Bureau’s American Community Survey (ACS) in 2008-2010, the most recent year data is available, on newlyweds who marry spouses of a different race or ethnicity, and compares couples who “marry out” with those who “marry in.”

Nationwide, 8.4 percent or one in 12 of all marriages in the U.S. are between spouses of a different race or ethnicity, the report found. That’s more than double the share in 1980, the first year Census data on interracial marriages is available, when 3 percent of newlywed couples were interracial. About 15 percent of newlyweds in 2010 alone were interracial couples.

“Intermarriage in the United States tilts west,” said the researchers. The West had the highest number of interracial marriages between 2008 and 2010, where 22 percent, or approximately one in five marriages, were between people of different races, followed by 14 percent in the South, 13 percent in the Northeast and 11 percent in the Midwest.

In Maryland, 2.2 percent of more than 108,000 marriages performed in that time frame included White-Black mates, whereas less than 1 percent of almost 12,000 marriages performed in the District consisted of White-Black couples.

Hawaii has the largest rate of interracial marriages, where four out of 10 weddings between 2008 and 2010 were between interracial couples, mostly White and Asian mixed couples. Other states where 20 percent or more of the couples intermarried are all west of the Mississippi River. Top states for marriages between White and Black intermarried couples are Virginia (3.3 percent), North Carolina (3.2 percent) and Kansas (3 percent).

The Pew Center noted “sharp differences” in what groups chose to marry outside their race. Black men are more than twice as likely as Black women to marry someone outside their race. Nearly a quarter of all Black male newlyweds in 2010 married outside their race, compared with just 9 percent of Black female newlyweds. About one in six Black newlyweds married outside their race.