There's a flaw in your logic though...
Any user with an Intelligence scale of 10 (or even 9) wouldn't need to bother phoning technical support. You won't be speaking to the geniuses, just all the idiots, so you can't really compare the numbers to get an average :-P
Sure the average user who phones you is an idiot, but that's the kind of calls you'd expect to get in a support center :-P