A recent article (Lee Sigelman, Steven A. Tuch, and Jack K. Martin, What's in a Name?: Preference for "Black" versus "African-American" among Americans of African Descent, Public Opin Q 2005 69: 429-438) reports on the results of "a nationally representative cross-section of African-American adults . . . who at the time of the interview in 1998--2000 were either currently employed or recently unemployed . . . in the coterminous United States, and had telephone access." The conclusion:
Of the 2,382 respondents to whom the question was asked, 1,146 (48.1 percent) voiced a preference for "black," 1,173 (49.2 percent) said they preferred "African-American," and 63 (2.7 percent) declined to express an opinion. Thus, opinions were split almost evenly between the two terms. Comparing these figures to findings from the surveys cited above suggests that the popularity that "African-American" achieved during the early 1990s did not grow during the ensuing decade and that, if anything, "black" has enjoyed a modest resurgence.
The statistical margin of error on a survey of this size is roughly +/-2%, so the results are a tie.