From the article linked above...
"A well-trained police officer will expend a minimum of 2,000 to 5,000 rounds per year, yet may never fire their weapon in defense. There is a significant disparity between rounds fired for training and those fired in a real world scenario."
I know dozens of cops, and they don't fire that many rounds in a lifetime, let alone a single year.
Might explain why PO's/LE only actually hit what they are shooting at <40% of the time. Wonder how many rounds the average CPL/CCW holder shoots/year?