The medical marijuana movement and hyperbole often go hand-in-hand. It wasn't more than a few years ago that the office of George W. Bush's drug czar spread the rumor that there were more pot clubs in San Francisco than Starbucks coffee shops, a drum they banged loudly and proudly (and one that, upon the slightest inspection, turned out to be mostly made up).
Some statistics you can prove, some you need to estimate. Numbers from the US Census — which say there are 48,000 African-Americans in San Francisco in 2010 — are a mixture of both. The number of medical marijuana patients in San Francisco is almost entirely an estimation — there's no “master list” of people recommended marijuana by a physician sitting around in a cop's drawer — but is guessed to be about 30,000 on the low end, and over 50,000 on the high end (it was about 45,000 a few years ago, according to medical marijuana advocacy group Americans for Safe Access).
So: More medical marijuana patients than black people in San Francisco? Quite possibly. And, if not now — as the black population dropped 20 percent from 2000 to 2010, according to Census figures — almost definitely soon.