This sounds about right:
CHICAGO, 25 (UPI) -- U.S. researchers found just 7 percent of respondents do not have the usual human tendency to favor one's own group and not form racial prejudices.
The operative phrase is "usual human tendency." Most people, in all places and all times, have felt the most comfortable with people who seemed the most like them and have been the most suspicious of those who seemed different. Prejudice comes from discrimination, which is not always a bad thing. Making quick judgments based on quickly processed similarites helped us survive as a race and thus became part of human nature.
That doesn't mean we can't be better than our nature. But we do have to recognize it.