Hi Jon,
Fuel tax in Europe is staggering by US standards. I really don't have a figure but the difference between your cost and ours is tax that's for sure - fuel prices are about the same world wide.
It just makes me laugh to see people who actualy have bothered to work out they can save $3 on a tank. That's about a liter and a half. I really do not know how much fuel I use (diesel station wagon) on 20,000 Km a year. Fuel is (according to other posts who have worked it out) about 6 dollars US a US gallon here.
Chris