Cave-based terrorist threat level in context.

UNDERNEWS: If those terrorists are so dangerous why aren't more of us dead?:

Detail of larger image via Undernews.

And we also came upon this chart from Wired in 2006, which while a little out of date (and includes 9/11), shows terrorist risk over a ten year span compared to other ways you could die.

Over a ten year span that included the 9/11 attacks, accidental gun deaths were more than double the deaths as a result of terrorism.