Only the French and Italians were less likely to say they were good at English, with 13 percent and 10 percent respectively.
The figures, from a 2011 survey, were released by Eurostat to mark Thursday's European Day of Languages.
They showed that English was far and away the leading foreign language learned throughout 28 European countries surveyed. A full 94 percent of children in upper secondary schools across the 28 countries were learning English, the figures showed.
French came next, but way behind, with 23 percent of children in upper secondary education learning it - and then came German with 21 percent of those children taking lessons.
Of the German adults asked, 78 percent said they knew at least one foreign language. Of those who said they could speak English, 16 percent said they were proficient, 34 percent they were good at it and 50 percent said their English language was fair.
Adults of working age were asked to rate their own foreign language skills. The countries where most people said they were multilingual were Luxembourg with 99 percent, Lithuania with 97 percent, Denmark with 94 percent and Slovenia and Sweden both on 92 percent.
The lowest were Hungary with 37 percent, Bulgaria with 39 percent and Spain with 51 percent. No figures were available for the UK, a Eurostat spokeswoman told The Local.