According to a Brandeis University studied scooped by the Harvard Business Review

White American families' median wealth (not including home equity) grew from $22,000 to $100,000 over the 23-year period ending in 2007, while African-American families' median wealth remained virtually flat at just a few thousand dollars, according to a new study led by Thomas M. Shapiro of Brandeis University. In each year of the study, at least a quarter of African-American families had no assets at all.

Check out the Brandeis study here