Every country gets at least 6 seats, and big countries get fewer seats, relative to their population. So votes in small countries have by definition more voting power. Voter turnout will have a large impact on voter representaion - if turnout in a country is higher then the individual vote has less impact.
Given that Europe votes at the end of this month for a new European Parliament, I thought I'd take a look at the data myself.
But we also need to highlight which countries have compulsory voting, as the turnout percentage for these countries will be particularly skewed. Countries with compulsory voting are highlighted in green.