"Earlier, cruder studies, done before direct genetic testing was feasible, suggested that African-Americans were 25 or even 30 percent white. Shriver's project is not complete, but with data from 25 sites already in, he is coming up with 17-18 percent white ancestry among African-Americans. That's the equivalent of 106 of those 128 of your ancestors from seven generations ago having been Africans and 22 Europeans.

According to Shriver, only about 10 percent of African-Americans are over 50 percent white"
[link to www.isteve.com]

That's the highest number suggested by studies, but it's true. That's why black Americans look different from Africans.