Very impressed with gas mileage

I’m not exaggerating or telling tales. 27.8 miles per gallon averaging 60-70 mph. I would have not believed it myself had I not documented it. I traveled 78 miles and used 2.8 gallons each direction. I was assuming I would get 16-18 mpg. That’s why I documented everything to settle my curiosity.
While I will certainly agree it is entirely possible to do it on one trip, that is not the correct way to figure fuel mileage. Fuel mileage is calculated over time with many different trips and then averaged together. You cannot just take one trip and decide you're getting 28MPG. That's not how it works.