Tsunami armor chance

[hhsu]

So i killed 500 axolandls to try to figure out the chance, i got 29 pieces, with a 25x luck, so that means it was more than a 1/500 chance, but im still not sure, because i did a test with 200, and that was a 1/1000, so I'm not sure but just narrowing it down for people who want to know

 

[solfyn]

level of luck ?? 100 or 70?