Ethanol fuel fix?

What percent ethanol?

My unit has run 87E10 since 1999 on the same fuel system. It has never seen anything but 87E10, except the one morning she went down the track, when I put in a lil "hi-test",lol.
750DP, Mopar HO pump, regular steel 3/8 fuel line,with EFI jumpers, no inline front filter, but yes EFI canister at the back, yes on the suction side..