Hispanics have edged past black Americans as the nation's largest minority group, new figures released today by the Census Bureau showed. The Hispanic population in the United States is now roughly 37 million, while blacks number about 36.2 million.

The figures, the first detailed findings on race and ethnicity since the 2000 Census was released two years ago, confirm what demographers have anticipated for several years. The new numbers are based on new population estimates from July 1, 2001, that were compared with the census figures from April 1, 2000.

The figures showed that — during this year — the Latino population grew by 4.7 percent, while the black population grew by just 1.5 percent. The white, non-Hispanic population, estimated at roughly 196 million, grew by 0.3 percent during the same period.

The explosive growth in the Hispanic population results from higher birth rates and from a huge wave of immigration in the last decade. The Census Bureau counts all people residing in the United States, whether they are legal immigrants or not.

Ethnic 'definitions' are imprecise

In many ways, the new figures are an indication of the growing multiculturalism in American society and the change in the way the Census Bureau allows people to classify themselves. The 2000 census, for the first time, allowed respondents to choose more than one race in identifying themselves. In addition, Hispanics, a cultural and ethnic classification, can be of any race. In contrast, 'black' Americans are defined by race.

These blurred racial and ethnic boundaries make precise distinctions between Latinos and blacks difficult. Latinos can belong to any racial group, and are often mixed race. While nearly half of the Latinos identified themselves as white in the census, an equal number checked more than one race. In addition, some black Latinos identified themselves solely as black.

And while the general African-American population is slightly smaller than the general Hispanic population, the number of Americans who declared themselves as black "in combination with one or more other races" is now 37.7 million, slightly higher than overall figure for Latinos.

"The statistics are in the eyes of their beholders," said William H. Frey, a demographer at the University of Michigan. "What these numbers reveal is a bit of a conundrum. But advocacy groups, policy people and politicians will pick the interpretation of them that works best for them at any given time."

How is this change significant?

Much of the social and political impact of the population surge may not be immediately apparent. Roughly one quarter of Latinos living in the United States are noncitizens. And while there has been a significant migration of Hispanics to cities in the South, Midwest, and central plains, more than 50 percent of the Latino population remains concentrated in Texas, California and New York.

However, according to Roberto Suro, director of the Pew Hispanic Center, a Washington-based research and policy analysis organization. "It is a turning point in the nation's history, a symbolic benchmark of some significance. If you consider how much of this nation's history is wrapped up in the interplay between black and white, this serves as an official announcement that we as Americans cannot think of race in that way any more."

In addition to their symbolic significance, the figures carry important implications for the allocation of resources. In recent years blacks and Hispanics have often felt in opposition in seeking financing and political representation, and the new numbers could bring fresh tensions.

Ron Walters, a University of Maryland political science professor, doubted that Latino growth would have much impact on what ethnic group influences national politics.

"Blacks are more culturally cohesive," he said. "Latinos are far more disunified because they have many, many ethnic groups. They're going to have to mobilize around the issues of language and immigration to thrust them into the political mainstream. There's a question in my mind as to whether the Hispanic community can do that."

The Hispanic lead is expected to increase significantly

The current slim numerical gap between blacks and Hispanics is expected to widen significantly in the next decade. Deteriorating economic conditions across Latin America, say many demographers, will continue to spur immigration. The birth rate among Latinos is also higher than among blacks.

However, researchers expect the spurt to level off in a generation or so, as economic stability leads to lower fertility rates and Hispanics intermarry with other groups with some choosing to identify as black, some as white, and some as a combination of one or more ethnic groups or races.

"It will only get more broad and more complicated," said Mr. Suro. "It's a reminder that we will increasingly, as Americans, need to find new ways of categorizing people and talking about their differences."