I understood the author gave some examples where the number of ubuntu users would be higher than expected, but didn't really try to get a level of accuracy in c

I understood the author gave some examples where the number of ubuntu users would be higher than expected, but didn't really try to get a level of accuracy in conclusion. The difference, say, between 10,000 and 1,000,000 users is pretty high. A comparison relative to other OS users would be helpful.