I was googling it, and I'm still unfulfilled in my search for the answer.
I heard once that only 5% (or was it 1%) are able to do it...
Also that only 1% of the world's population have the necessary genes to make it to the Olympics (never mind the work or anything like that) - and that 1% diminishes as some people couldn't be arsed with the hard workouts...
Anyway - back to the original question - What percentage of people can run a mile in under 5minutes?