I'm not going to play semantic games on this. I know that there is no exact time-series of incidence of right wing violence out there simply due to the fact that there will be "no, that's not really right-wing" objections to events composing it, and you know that as well. As a result, you can't point to a concrete rise because you can say "well how many were occurring in the past?"
If one responds, then you can discount that as "Those weren't really right-wing." and the circle continues. It's pointless, and I'm not pursuing it further.
I am interested, however, to see how any of those weren't right wing, or at the least related to key points of right-wing ideology. At best, I would say your best argument would be toward the sovereign citizens' shooting, but at the same time, the sovereign citizen movement is traditionally linked to the Patriot movement, which I would not exactly call left-wing.