In Alabama, Romney took home 36% of top earners, which is 5 points more than Santorum, and 11 points more than Newt Gingrich.
The story was much the same in Mississippi, where the former Massachusetts governor won votes from 34% of individuals who reported incomes above $100,000. Santorum won among voters making between $50,000 and $100,000, while Gingrich had his best showing with those making less than $50,000.
The contrast is even more striking in states like Michigan and Ohio, where Romney did well enough to win the primaries.
In his home state of Michigan, Romney won 48% of primary voters making more than $100,000. Santorum was second with 34%.
In Georgia, where every candidate in the field was trounced by Gingrich, Romney still won among voters making more than $200,000 (Gingrich won when the limit was extended down to $100,000.)
(source)
