What is there to "huh?" The statement stands for itself. Far fewer than half of the Mexican population identifies as practicing Catholics. As in, fewer than half the Mexican populace say that they attend mass, receive the sacraments, follow the teachings, or do anything that marks them as a Catholic aside from being baptised. And these are old studies in general. If the indicators are anything to go by, the numbers are even less today.
http://www.catholicnews.com/data/stories/cns/1200688.htm
http://wayback.archive.org/web/20060901122224/http://www.ns.umich.edu/htdocs/releases/print.php?Releases/1997/Dec97/chr121097a
P.S. Do you have links for anything you've said thus far?