To put it in perspective there are 265 million (4% of the worlds population), active football players in the world according to FIFA.
This figure does not take into account people who just enjoy a kick about with their mates in their free time.
MMA will never, ever, surpass football in terms of popularity. For the likes of South America, most of Africa and Europe football is part people's culture.
source
http://www.fifa.com/mm/document/fifa...9384_10704.pdf