I was going to say the exact same thing. I think not only what you mentioned but also how much time they spend with the animals should be considered. I'm sure those killed by pigs are farmers that spend a lot of time with pigs. The attacks over the time around humans ratio should be looked at.

I think these should take into account the number man hours of people on pig farms vs. that of water when comparing such statistics.

My guess is if you spend 1 hour swimming in the ocean and 1 hour working on a pig farm you are more likely to be eaten by a pig.