Scanning is not a 'high popularity' activity. And since, whether they're correct under local law or not, many think it's 'against the law' to listen to the cops, those who do scan sometimes tend to be 'low profile' about it.
Then there's the nutcases like me, who carry at LEAST one scanner everywhere, possibly along with a ham HT or a GMRS HT (or both).
If you really want to guestimate how many scanning types are in your area, you could ask a local scanner selling store 'about' how many they sell a year, or something, I guess. It used to be more popular before the 'Trunking' era arrived, as it used to be a lot easier to set up a scanner without much knowledge of what you were doing.
And, sadly, as more and more of the 'meaty' listening targets like police and fire encrypt their comms, fewer and fewer will remain interested in scanning. Just the way it is. You still have railroads, marine, and other stuff out there, for now.
Eventually, ALL on air comms can be expected to be both digital, and using channel sharing methods like CDMA, so unless 'scanners' become available that can handle the high-tech fancy modes, at that point, scanning for much besides ham radio will be gone, and with no market, the manufacturers stop making them. Hopefully, not, eh?
