[tex-live] TL 13 -- how many maintained installations are there?

[AW]

Hi,

while TL 13 will be frozen soon, I'd like to thank to all the people who 
helped creating and maintaining it.

You, e.g. Karl, Norbert, and many others have been working for us, the users. 
But how many are we, the users? 

Clearly, you cannot count all of the tex-live installations which come with a 
Linux distribution. You never know, whether it will be used ever. 

So maybe we could get a rough estimation of active users by counting the 
computers which update a given TL 13 installation. 

Is there a way to find out how many computers have updated TL 13 using tlmgr, 
at least once? Or is this somewhere between difficult and impossible to find out, 
because the mirrors don't count how often an update has been downloaded?

The introduction of the companion, 2. ed., made a forecast (I'm refering to 
the German edition): LaTeX wil be used extensivly for another 15 years until 
2020. 

If possible without too much time and effort, I'd like to find out how we 
perform, ten years later now. 

Regards,

Alexander