and a native speaker-only quiz sounds nice. I'll take a shortcut for that one and wait for you to make the rest :D
besides the uk and ireland which european country has english as an official language?
looked it up, only malta as far as I can see, and that wont add much to the totals. (half a million max)
I don't think even the NSA has the data supposedly collected in this quiz...
So the next on the list would be about half the number of dutch speakers (in Europe, though the numbers from the americas would not add a very significant amount, maybe 1 mill)
Spain population 46 mil.
Well, there's 8 mil. mute spaniards I guess x)