*Insert Michael scott "Dear god no" gif here*
19 different corruptions.
16 have 3 different levels of strength.
That's already 48 different levels at which you can get corruptions. add into that the ones that have only one set level, or two, brings that number up to 52.
So when you want a single corruption you're aiming for, regardless of corruption level? that's already a 1 in 19 chance of getting the right one when you happen to get a corruption proc, roughly a 5% chance.
Now add into that wanting it at the right amount of corruption. The right strength. A 1 in 52 chance. Or... a 1% chance.
That's "RNG done right", for gear?
To tack on, I might have goofed the math in my rush to respond admittedly, but I'm sure someone will double check it. Someone's always quick to double check on the internet.