Between 4500 and 5000 miles per year.
And I get around 6.5mpg average, (it's a Ford V-10), when towing another vehicle.
Have a Scan Gauge II that gives me instant mileage in the motorhome, about 2.5 mpg going up the mountain and 9999 going down the other side.
Gas prices around my house are $3.61 to $3.65.
Just said $3.69 because that's the price that matches the ones on the gauge, for my 75 gallon tank.
If I had a 38' diesel instead of gas, I would get better mileage, but diesel costs more, $3.99 to $4.05 here.
Beside, diesel motorhomes cost more than gas ones, and I couldn't afford one. (still can't)
Vern.