WASHINGTON: - Americans voters' preferences about the two presidential candidates are sharply divided by race, a Washington Post-ABC News poll found, as Sen. Barack Obama, the first African-American on a major party's presidential ticket, enters the 2008 campaign for the White House. Obama enjoys an overwhelming 90% of support from African-American adults, the poll found, while Republican Sen. John McCain garners just 7%. McCain, meanwhile, gets 51% support from white adults while Obama takes 39%. Among all adults, the poll found, Obama enjoys a lead of six percentage points over McCain, 48% to 42%. Among those considered most likely to vote, however, the presidential race is a draw: McCain scores 48% to Obama's 47%. While 39% of white adults support Obama, a majority of whites also view the Illinois Democrat as a "risky" choice for president. Among whites, 52% said Obama is a risky pick, compared to 47% of whites who said he is "safe." Among blacks, 78% found Obama safe versus 21% who said he is risky. Whites made up 77% of all voters in 2004 while blacks represented 11%, the Post reported, citing network exit polls. Both black and white adults believe Obama's candidacy will help race relations in the U.S. more than it will hurt them. However, African-Americans are far more optimistic, with 60% responding that Obama's candidacy will help race relations. Only 8% said it would hurt and 31% said it wouldn't make a difference. Among white adults, 38% said Obama's candidacy would help, while 17% said it would hurt race relations, and 43% said it wouldn't make a difference. In the same poll, almost half of all Americans say race relations in the U.S. are in bad shape and three in 10 admit feelings of racial prejudice. The poll was taken June 12-15 among a random sample of 1,125 adults, including additional interviews with African-Americans, for a total of 201 black respondents. The full survey's results have a margin of error of plus or minus three points. Obama was taking a break from campaigning on Sunday, spending the day in Chicago with no public events. McCain was also taking a rest from the campaign trail Sunday.