Gentlemen;
I think Jayson's correct & the percentage will stay around 10-15%, with more 'mixed fuel' being made, not a higher percentage etc.
That (of course) is a 'nationwide' probable adverage and the 'mid west' is really where It's needed and they (CARB)* have NO juristiction there.
The EPA doesn't care what they think anyway, even in California.
Hapy trails.
(*) The California Air Resources Board, a State "bureaucarcy" only.