I wonder what you call "adherents of Islam" and "Muslim population". As far as I know they are many groups that claim they are Muslims and they sometimes don't

I wonder what you call "adherents of Islam" and "Muslim population". As far as I know they are many groups that claim they are Muslims and they sometimes don't recognize other groups as Muslims (I have many friends that are Muslim and I am pretty sure they would tell you that the 40% your are mentioning are not Muslims) so I think it would be a bit weird to consider all of them as being "Muslim population" as if they were a single group while there are clearly just separate and unrelated groups that happen to claim the same name.