I am not sure, but I'm very suspicious of some of our data. So few wolf attacks kind of sounds like global warming to me. Sort of like they only kill the sick and old. I know that's crap. I listened to a professor giving a lecture to his students on a field trip in the Lamar Valley in Yellowstone. I have never heard so many false statements on any subject before in my life.
I have heard stories from old people in Europe about dragging ropes with slip knots behind the sled in winter to keep the wolves back. No one could afford a gun, and wolves didn't like stepping in those dragging ropes. I'm not 200 years old so I can't verify that. Could be the other end or the spectrum from that crazy professor.