Even with the ethanol (10%) I am still around 20 mpg, I don't count the MPG, I think of it as miles per $ and on the A I don't really worry, the last 20$ I put in --I think it was March --so far--a 42 mile round trip, 5 mile joyride, then work and back--10 miles, a parade-with a ride --5 miles and still more than 1/4 tank --it was empty( the gauge was at 0 and didn't move on bumps) like about to run out when I put in the 20 ---I blame my poor mileage on neglect, havn't done much more than adjust the points and shake the dirt out of the carb for many years.
For the parade it was about 80, I still have the March winter gas, and the ex man is cracked and puffing on the fuel bowl --yet still no vapor lock during the during the idle speed in 1st parade.