Another way you could map it out is by pc operating system. There was a large wave of XP's in years past. That transitioned into win Vista. That's what i see more commonly these days.

A lot of the Win 7's and above are still in service.

The whole free upgrade to Win 10 kept a lot of the older machines in service so that's created a pause in towers entering the waste stream.

There was a fairly significant shift from towers to laptops in the Vista years.



Tablets & handhelds became popular in Win 8 and beyond ?