I thought that was weird too (several other things on the site seem that way at first, until they explain something like "oh by the way, we filtered only for murders, terrorist acts, etc., not naively by number of deaths"), but it's the definition of "per capita" that is weird. If you look at the table, per capita is number of murders per travellers (to that country) times 100000, which seems fairly reasonable, though indeed the amount of time there also should factor into it (maybe I still didn't read far enough :).