How is this for hard data? The Ratebeer website database now includes over 16,000 breweries with 2,600 added in 2013 alone.
They also have 300,000 users. (Some of which obviously are inactive, others hyperactive) There are over 5.2 million user-submitted beer reviews. AND as of February 2014, reached its 250,000th beer in their list of beers. (again some inactive or seasonal).
How fast will it take to double that?