All of the European data comes from the E.U.’s European Energy Portal website. U.S. and Canadian data come from the respective Automobile Associations.
From this recent chart in the Economist, you can see that the bulk of the premium costs in most European nations is due to higher taxes and duties on crude and gasoline. Many nations recognize oil as a finite resource, and are utilizing gasoline taxes to reduce oil imports, create a more efficient transportation system, and better prepare for longer-term oil price volatility.