I finally got to drive my 2014 Volt in electric mode all day. I used 7 kw to go 30 km. (as an aside, I calculated that it cost me 70 cents for my day )The display shows 75 percent efficiency. My first drive of the day I got up to 89 percent but it dropped to 75 percent for the rest of the day. I mostly drive around my small city. I also do a lot of short drives. Is that why I cant seem to do much better than that?