I admit my gas mileage is not the lowest as I average in mixed conditions & light spirited sprints to the speed limit about 11.1 l/100. If I am extra bad
its closer to 12 l/100. Thats about 21.19 - 19.6 mpg
if I am boring I would assume a mixed 10 l/100. Freeway only, I can cruise near 7.1 l/100 or 33.13 mpg. More realistically its probably 9 l/100 or 26.14 mpg.
In any case I tend to average about 450-500 km between fill ups.