The count shown on the Area 51 topbar sites-switcher tooltip (hover over Stack Exchange logo on the top-left) is missing the count of Stack Exchange Network sites.
Area 51 topbar sites-switcher tooltip says:
A list of all Stack Exchange sites
Whereas, on StackExchange.com it says "A list of all 154 Stack Exchange sites" and most of the subdomains i.e. *.stackexchange.com shows "A list of all 149 Stack Exchange sites".
But, as for the Area 51 tooltip goes, it's totally missing the count.
Here is the screenshot of it:
Can anyone please explain this?
P.S. My original question was marked as a duplicate by Shadow Wizard. But it was not exactly duplicate. I have removed the duplicate content from this question. Please note that Werner's question is about the difference in number of communities on Stack Exchange site whereas my question is about "missing count".