That is sales from the period (quarter).
CPUs sold in previous quarters are not counted... it uses the data given by AMD and Intel.
For example the example of last quarter I posted...
Units Share is based on AMD data.
Revenue Share is an estimated by Mercury... so I didn't take these as very accurate because they calculate based in the avg. price of the CPU sods that could give some small errors.
Look at the 23.9% in the graph for Desktop and this other pic... they are the same.
From 2015 to now AMD grew around 20% in Server market share (they gone from near 1% market share to today 20%)... it is by far the biggest jump they had with Ryzen (2017).
Talking about Desktop only they gone from 9% to 23%... near 15% increase in a decade.
Intel still dominates by a good margin.
BTW this is the overall graph for Market Share quarter by quarter with some missing data because AMD or Intel didn't share all segments in these quarters.
But it gives the overall look... AMD x86 (all CPUs) market share grew from 13% to 20% with Ryzen.