If you constantly/more or less shift through the gears (i.e: accelerating and seeing that needle dissapear over 30 in the "gas consumption" (for lack of actual term) dial.) Then you'll be seeing that other gas tank needle go down fairly quickly.
Though, if you take it easier...and try to resist all the "enthusiastic driving" temptations you might encounter. It's not so bad. Good size tank too.
If you want, I could closer observe my own consumption.
It'll be in Canadian dollars and metric system though... :yup