I don't get paper receipts at the gas station, but I do keep track of my fuel expenditures. Based on the $261.00 spent on fuel since I got my EC in November (the 9th, to be exact) and current odometer reading of 3,326 -- factoring out that first full tank of gas from the dealer -- and the price of gas in my area averaging $2.69/gallon for that period, the numbers support consistent 30+ mpg fuel economy. The numbers I see on the dash also regularly show ~31 mpg on my daily commute.
Let me point out that trip type, duration and driving style greatly affect mileage. I drive my car 65 ~ 70 miles per day, 4 days a week. I work from home on Wednesdays and drive the wife's car on the weekends (more on that later). My commute is evenly split between 4-lane highway and a 2-lane country-ish route. The highway is a straight shot of 15 miles with speeds around 65 mph. The rest is usually driven around 45 ~ 50 mph. The thing is there are few stops and steady speeds. Perfect for fuel economy. What little else i drive my car around town doesn't seem to drag my mileage numbers down.
My wife's car (2019 Jeep Cherokee) is rated 23 mpg city/ 31 mpg highway. I can tell you that in the year she's owned it, we've NEVER seen anywhere close to 31 mpg. and honestly she rarely averages above 22 mpg. You see, her daily "commute" to work is close to a mile ... maybe and here other weekly use is always short trips close to home. We drive her car on weekends just to put some highway miles on it, but as my short trip driving doesn't negatively impact my mileage, our longer weekend trips don't have much effect on her low ratings, either.