Indirectly through serial concentrators and RTUs and Scada access, almost 100%.
The FERC / NERC security standards that fell out of this event are largely a bad joke, but had the benefit of at least requiring North American utilities to do something at all.
Any transmission operator of size and most generation operations effectively require real time Scada for anything of meaningful capacity and they're sure not paying someone to sit next to it reading numbers off over a phone. They may not be IP addressed individually but to put it in perspective, I had a communication engineer tell me with a straight face that the fiber mux I telneted into over their local wifi wasn't internet connected, and thus the protection relays on the 500 kv substation the next building over were serial only -- over said fiber cables.