The decline of serial killers and rise of the sharing economy (opens in new tab)

It's an interesting article, but the graph is puzzling. The Y-axis is labeled Killers/Teams. Teams? Given the title of the source was it teams of killers vs lone killers? Was there a drop in killers or rise in teams or both?

I, for one, do Not believe this study. Decline of serial killers!? What would they say next? That Dexter is not real?

Great! And very interesting. I wonder why there is a decline in the number of serial killers?

With all the superheroes coming out, the killers should be scared!hehe!