Ok, I found the piece of paper I jotted my numbers down on. Here are my totals (this is NOT the end of tour, you are going to have a few more kills in every category I think, but not a difference of 3%).::
Total Kills: 205,896
I subtracted the kills accumulated by these units-
Chute: 1330 Kills
Gunner: 445
M3: 1324
M16: 6931
Osty: 9097
Panzer: 3184
LVT: 731
LVT: 442
Ptboat: 4080
ShipGunner: 6353
B17: 4633
Lanc: 2008
B26: 3289
Ju88: 420
C47: 328
TBM: 529
IL2: 1878
Arado: 31
After subtracting those I arrived at a total of 158,863. This number is kills achieved by fighters.
Then I took the N1K2 total of kills, which was 23,847, and subtracted all of the kills it had on the above units. The total "fighter kills" that the N1K2 had was then 18,785. Then I divided 18,785 by 158,863 to arrive at a figure of 11.82% of kills.
How'd you do it?