The "2" makes it apparent that your iMac has connected to the App Store at some point, and I was wondering if there was something to be learned.
Apparently it came via Notifications before I could disable ALL Notifications. Since then nothing has been added; ergo, frozen at "2".
Notifications got it from somewhere else...Software Update, I assume, so disabling it wouldn't have anything to do with anything.
Your number is probably frozen at "2" because you're running an OS that's pretty much unsupported at this point and just hasn't had any new updates pointed at it lately.
