I agree that a lot of people speak two languages. But man, I've lived in several countries in Europe for many years, and even the average university student doesn't really speak English (and I work at the university so I interact with many of them). Even in countries like Belgium where there're three official languages!

However, I'd agree with that the average educated person can somewhat communicate ideas in a second language. This is what polls usually show, around 30% to 50% of people.