This information is a bit dated but definitely in the ballpark.
From Digital Journal:
Who Do The Rich Vote For?
In the blog “Election 2008: what really happened”, the author states: “As with previous Republican candidates, McCain did better among the rich than the poor.” He includes some charts that support his contention. The first chart shows that Republican vote share is very low with individuals in the lowest income groups. The Republican vote share increases dramatically as income rises....MORE
The Republican vote share peaked in the 60 to 70 thousand dollar range and then declined gradually to the 90 thousand dollar range before climbing again to 150 thousand dollars. The second chart indicates that the Republican vote share peaked again between 125 and 150 thousand dollars. After that it declined gradually as income continued to rise....
HT: Chicago Boyz