If I am going to interpret your question verbatim, I would feel pretty confident in saying 99.9% of phone calls will traverse a VoIP trunk when they are connected. Does that mean it’s a VoIP call?

You have to remember the Public Switched Telephone Network is a bunch of different phone providers interconnected through all kinds of different protocols. Anytime you’re making a phone call, it’s going to hit a VoIP trunk at some point regardless if you’re calling from one of the few true analog lines left.

And as many pointed out in this thread, even if you have an analog line at your home or office, the chances are pretty high it is just a “handoff” that is probably connected to a VoIP device right on the other side - whether it’s at your site or at the providers central office.

There are still true copper lines and T1s out there but providers really want to get out of that space and are jacking up the rates for these services so high that it is forcing people to move dedicated VoIP service.

Side rant: I just really wish fax machines would go away. They are a challenge sometimes to get them working over a VoIP connection…