WASHINGTON -- Within the nation's black population, there are now two distinct communities: one made up of the affluent and the middle class; the other, of the poor. Both are growing -- and they are also growing away from each other.
At the same time, the "remarkable progress" of black Americans in the post-World War II era appears to have slowed during the 1980s and even "regressed" in some areas.
These are among the conclusions of a new demographic study, "African Americans in the 1990s," made public yesterday by the Population Reference Bureau, a private, non-profit research organization based here.
"The economic gap between rich and poor blacks is growing," the study found, adding that "the middle-class blacks of the future may feel little in common with poor blacks because their experiences will have been dramatically different in so many ways."
But racism -- "one of the major forces that led blacks to rely so heavily on one another," is still "very much evident," the study said.
At a news conference called to release the findings, demographer Taynia L. Mann explained that blacks who are in the middle class have been able to take advantage of civil rights opportunities, while poor blacks, largely in the cities, continue to remain socially and economically isolated from the American mainstream.
Other researchers and analysts have described poor blacks as making up an "underclass."
Kelvin M. Pollard, another of the study's four authors, estimated that 31 percent of the 30 million blacks living in the United States at the time of last year's census had incomes below the federal government's official poverty line of $12,000 a year.
Meanwhile, there has been a growing concentration of blacks in high-poverty areas, census tracts where at least 20 percent of the residents live in poverty, the study found.
Between 1980 and 1990, it reported, the number jumped by 19 percent, while the nation's black population grew by 13 percent.
During the same period, the number of black families with annual incomes of $50,000 or more doubled, the report said.
In 1967, the report said, one in 17 black families was middle-class. By 1989, the figure was one in seven.
Actually, the study found, the number of middle-class black families fell during the recession of the 1980s and then saw "phenomenal growth": There were twice as many in 1989 as there had been just a decade earlier.
What happened in the 1980s to slow the progress not only of middle-class blacks, but all blacks? Said the study: "Many observers feel that Ronald Reagan's presidential administration . . was particularly harm ful to black socioeconomic advancement, erasing civil rights gains and promoting a general anti-minority climate. Others see a myriad of factors. . . .
"The urban poor appear stuck in a quagmire of unstable familiesintermittent employment, welfare dependence and the temptations of crime."
Ms. Mann pointed out that while blacks remain the nation'largest minority -- one of every eight Americans -- they will be replaced "early in the next century" by Hispanics.
The growth rate of Hispanics over the last decade was four timethe 13 percent rate of blacks, while the number of Asians in the United States is increasing at a rate eight times that of blacks, she said.