I'll be 115.
Secret, it's big oil that has determined MPG for the past 50 years as well.
It's a factor of fractions, so much kerosene/jetfuel/fuel oil v. the lighter stuff , gasoline , etc..
It all has to go somewhere, you can't compress a liquid, so the math has to be worked out in advance.
I'll be 81. Wanna hook up?