That's a pretty high kill rate. I have been known to run such deadly adventures as the Tomb of Horrors and the old Judge's Guild adventure Dark Tower, so I'm not unfamiliar with killer dungeons. I read Rappan Athuk back in the 3.0 days I think and found it interesting, but I never got a chance to play or DM it (Crap was that more than 10 years ago? Damn, I'm old.) I've heard good things about Slumbering Tsar as well, usually folks praising it as more Sandbox than most of the official Pathfinder stuff. But I've also heard it is deadly. I haven't lost a character in over a year, so I guess I'm over due.