Marriage across racial and ethnic group lines has grown in the United States at a remarkable pace over recent decades, demographers report, but the U.S. Census Bureau has yet to take this into account in its projections.

For example, the bureau has predicted that in 2050 non-Hispanic whites will make up 52.7 percent of the U.S. population, compared to 75.7 percent in 1990; Hispanics will account for 21.1 percent; blacks 15 percent; and Asians 10.1 percent. But these neat categories don't account for the growing mixed-race or creole population since the Supreme Court struck down the last of the states' antimiscegenation laws in 1967.

• Between 1960 and 1990, interracial marriages skyrocketed by more than 800 percent.

• Roughly one in 25 married couples today is interracial, and there are more than 3 million children of mixed-race parentage in the U.S. -- not including the millions of Hispanic mestizos and black Americans who have European and Indian ancestors.

• Nearly one-third of Hispanics are married to non-Hispanic whites, and among Asian-Americans or Orientals, 36 percent of native-born Asian husbands and 45.2 percent of wives have white spouses.

• Interracial marriage is highest among American Indians -- with slight majorities of both men and women more likely to marry whites than other Indians.

The rates for blacks who marry outside their race have risen, but still remain much lower than rates for Hispanics, Asians and American Indians who marry into other races.

As a result of these demographic trends, experts predict that in the 21st Century, the U.S. population will no longer be crisply divided between whites, blacks, Hispanics, Asians and American Indians.