I got 6 (out of 6) on my oral English exam back in high school. I got 5 on my written exam. For context, I'm from Norway, and this was a small school in the middle of nowhere. I've had English speakers tell me that I write better English than they do. Still didn't get a 6 on the written English exam, though. I think that tells you something about the standard Norway maintains for teaching English.
@thor
I doubt plenty of native English speakers (in the US, based on my anecdotes) would score that well on Norway's written test, though I don't know if that's in line with the variance you'll see in native speakers of any language.