What is human error anyway?
I did find the 2021 version of this report on google scholar, It's here [pdf] .
p.11 lists a breakdown of what the reason behind the "human error" outages was. only 48% of them was actually an employee making a mistake even being part of the reason. 41% indicate improper procedure was (partially) at fault for the outages. is it even human error if the human follows procedure? yes, sure, but you can hardly blame it on the person making the "mistake".
Assuming this year's report includes this data as well, this would be great to know, as it gives important background on this article.