For this, I subtracted the white republican vote to the actual republican vote. For example, Indiana: 60-54 = 6. Unfortunately, 2012 didn't exit poll 19 states (including relevant states like Texas and Georgia) and DC. So I could only do the other 31. Mississippi was the highest at 34, and Maine was bizarrely -1 (but its close to 0 anyway). Of course, a lot of this depends on the % of electorate that is white, what other non-whites are voting (all Hispanics vs. all blacks makes a big difference), and so on, so a good correlation map could be made in the future.
Key:>30% = 0-4% difference
>40% = 5-9% difference
>50% = 10-14% difference
>60% = 15-19% difference
>70% = 20-24% difference
>80% = 25-29% difference
>90% = 30-34% difference
Numbers:
AL: 84-61 = 23
AZ: 66-54 = 12
CA: 53-37 = 16
CO: 54-46 = 8
CT: 48-41 = 7
FL: 61-49 = 12
IL: 52-41 = 11
IN: 60-54 = 6
IA: 47-46 = 1
KS: 64-60 = 4
ME: 40-41 = -1
MD: 55-36 = 19
MA: 42-37 = 5
MI: 55-45 = 10
MN: 49-45 = 4
MS: 89-55 = 34
MO: 65-54 = 11
MT: 59-55 = 4
NV: 56-46 = 10
NH: 47-46 = 1
NJ: 56-41 = 15
NM: 56-43 = 13
NY: 49-36 = 13
NC: 68-50 = 18
OH: 57-48 = 9
OR: 44-42 = 2
PA: 57-47 = 10
VT: 33-31 = 2
VA: 61-47 = 14
WA: 46-41 = 5
WI: 51-46 = 5