Internal documents reportedly say that Amazon suffers from 69 percent to 81 percent regretted attrition across all employment levels. In other words, "people quitting who we wish didn't."
I read that as "of 100 people who quit voluntarily, we wish 69-81 of them hadn't". But that number is meaningless without the context of how many people are quitting out of how many are there, not to mention onboarding processes and how fast new hires get up to speed.
From TFA.