In the Horizon Post Office case in the UK[1], over 700 individuals were convicted based on false accounting data.
I can't find what percentage of that total pleaded guilty, but I did find[2]: "Of the 39 successful appellants in the Post Office Scandal, 35 had pleaded guilty to at least one charge against them."
Personally, I'm not feeling 100% confident in the adversarial system right now.