"european" (currently 7 questions) and "eu" (currently 10 questions) are duplicate tags. "European" should be made a synonym of "eu".
I created a tag synonym, so anybody who files a question with eu will now automatically have it switched to european. This also applies retroactively to existing questions.
Thanks for your help identifying tags on the site--I know we've got a lot that are duplicates, or otherwise don't fit well within our guidelines, and getting those cleaned up is a great help to improving the quality and searchability of the site.