VHF use varies per the regions. There was no major conversion to use P25, what ocured was the capability to use P25, but most of my monitoring experience [New England and other travels] has been Analog.
There was Coordination with Canada [unkn on Mexico] and that is why the channels near the Border are different.
Take a peak at the
RR Wiki which has much [99.99%] of the channel plan. What is missing is our identification of the Local Repeat Sites/Info
There are a few states/wings where the CAP has access to a Statewide EMA/Mil [State] network and rarely use the CAP Allocations, sadly
What kind of progress has CAP made with switching to APCO25. ?? They dumped $42M into new equipment and forgot to match bandplan with Canada and Mexico. Some comms on HF but VHF is quiet.