Note too: I keep reading that blacks are Democratic as against Republican, "9-1." The exact proportion is at least 10-1. This is all based on the 2000 election, when 91 percent of blacks voted for Gore.
Accepting your statistic of 91% of black Americans voting for Gork (presumably, we are considering the proportion of those who voted, as opposed to absolute population) at face value, 91% translates very straightforwardly into a ratio of 10.11-to-1, thus, 10-to-1 is hardly inaccurate.
Come to think of it, it's a proportion rather similar to that of losers-to-winners among small stock market traders.
Do I suppose there is a similarity between these two assumptively dissimilar groups? There is, indeed, and bet your life on that one, m'friend. Perhaps the reasons for the similarity are obvious to you, perhaps not.