If only 49% of the population voted, and it broken down by race, ONLY 72% of the whites voted. Ur conclusion could be wrong and biased.
I think I found the numbers. I think the reference was to % of each race that voted, not the population. USA Today has a breakdown. 72% of the "white" vote, voted for Romney. 92% of the "black" vote voted for Obama. 70% of the hispanic vote voted for Obama. 73% of the asian vote voted for Obama.