I'm not really surprised at the numbers, everywhere I have travelled in Europe people seem to have a great grasp of English, even to slang sayings etc. They all have my utter admiration in their abilities. I know a little German (mostly about food I might add) and my schoolboy French. ....... gosh I'm jealous.
English originated in Germany with the Anglos moving to England, so its probably not that surprising that English, a Germanic language, is spoken in Germany.