New U.S. census figures that provide a snapshot of America's foreign-born population are challenging conventional views of immigration, race and ethnicity.

What it means to be African-American, for example, may be redefined by the record number of blacks—now nearly 1 in 10—born abroad, according to the report from American Community Survey data, which was released Wednesday. It found that Africa now accounts for one in three foreign-born blacks in this country, another modern record.

More than 1 in 50 Americans now identify themselves as “;multiracial.”; But the pattern of race reporting for foreign-born Americans, is markedly different than for native-born Americans. The foreign-born are more likely to list their nation of origin when identifying race or ethnicity.

For example, while 87 percent of Americans born in Cuba and 53 percent born in Mexico identified themselves as white, a majority born in the Dominican Republic and El Salvador, who are newer immigrants, described themselves as neither black nor white.

“;The concept of race and how we view it culturally has changed,”; said Elizabeth M. Grieco, chief of the Census Bureau's immigration statistics staff, which analyzed 2007 data. “;It's a part of not knowing where they fit into how we define race in the United States.”;

Recent arrivals “;might not be sure how to classify themselves,”; Grieco said. (The census treats race and Hispanic origin as separate categories.)

The changing perception of race is being driven largely by immigration and higher birthrates among the foreign born. While immigrants account for 13 percent of the population, the share of recent births to foreign-born mothers rose to 20 percent. As a result of intermarriage with native-born Americans, a growing number of American children—now more than one in four under the age of 6—are being raised by at least one foreign-born parent.

“;It's fair to say that we are approaching the shares seen at the peak of the last great immigration wave”; at the beginning of the 20th century, said Jeffrey S. Passel, senior demographer at the Pew Hispanic Center.

Kenneth M. Johnson, senior demographer at the Carsey Institute at the University of New Hampshire, noted that more that two-thirds of the growth of the Hispanic population last year came from births, not immigration.

“;You could shut off immigration tomorrow and the impact of the foreign-born on U.S. demographic trends would still be a powerful force,”; he said.

Among the nation's 37.3 million blacks, more than 8 percent are now foreign-born, compared with 1 percent in 1960. Of those, more than half came from the Caribbean. Some 34 percent emigrated from Africa, compared with 1 percent in 1960.

The census recorded 10,500 American blacks born in Africa in 1970; in 2008, the number of African-born Americans topped 1 million for the first time.

Seventy-eight percent of native-born Americans reported their race as white, followed by 13 percent who said they were black. Among the foreign-born, 46 percent identified themselves as white and 23 percent as Asian.

Since 2000, the Hispanic foreign-born population has increased 45 percent, to 18.5 million from 12.8 million. Latin Americans represent more than half of the foreign-born population.

Among all who identified themselves as Asian-Americans, which is often understood to mean born here, 67 percent were, in fact, foreign born.

How immigrants translate their own backgrounds and report their adopted identities “;have important implications for the nation's racial and ethnic composition,”; the Census Bureau said in the report.

Nicholas A. Jones, chief of the bureau's racial statistics branch, said that given the likelihood that foreign-born people would identify themselves as German or Irish or Nigerian instead of black or white, the bureau might eventually encourage people to provide more detailed write-in answers to how they define themselves.