I think "popularity" is virtually meaningless. For corporate or enterprise use, not all distros are going to be represented, just the ones aimed at that market: RHEL, SuSE, etc. debian or slackware or other distros based on them aren't going to be reflected in the results.
For end users, maybe there is slightly more validity, but although a distro being "popular" might lead someone to try it, at the end of the day people simply will use what they like best anyway, regardless of what is "popular."
Is there a particular reason for the question? just curious.