I can't say exactly what the numbers are, but anecdotally, there are a lot of "research" users buying tirz (and reta, for that matter) for a few bucks a week on the gray market. The better known sources sell out batches in a week or two, which amounts to 750K-1M worth of product (at gray prices, not retail). There's a reason you're starting to see regular news stories about it.

I'm curious how these below-the-radar users skew the numbers. Maybe not at all?