One of the indications that the guy above didn't really tend to read up the entire text and instead accusing or telling that op should put up some source link.

Is he blind or didn't really just see the link given? If not then he can search up for himself and there are lots of results that would pop out if you do really make out some search for this one.

About the rankings then it might not be precise but at least we do have the idea basing off with these numbers which indicates that these countries are really having
that big industry when it comes to gambling area but same as other said as well that there are other parts of the world might not haven't been known yet
but still can able to match up these numbers.