I have too much time on my hands these days as I'm recovering from some PRP ... I got curious about the cocaine thing. That information is based on statistics reported to a govt. agency named The Substance Abuse and Mental Health Services Administration. You get arrested, you go to the hospital, you go to rehab, they test blood and piss, that data gets reported and it's one of the SAMHSA's jobs to collate it.
As for the beastiality thing, apparently it's cases that were actually reported which probably means someone ended up in an emergency room.