Here is the data:
http://greenercars.org/greenest-meanest/greenest
I don't see how they calculated the "green score" though.
The calculation might be somewhere on this page:
http://www.aceee.org/press/2015/02/electric-cars-gain-ground-environmen
Ah here it is, how we determine the ratings:
http://greenercars.org/greenercars-ratings/how-we-determine-ratings