For those wondering why 10%, Neutron Jack Welch probably magicked this number up in the 80’s and managers have used it ever since:

“DAVIES: Manager of the century - wow. You know, apart from closing plants that he deemed too expensive or moving operations overseas, he had an idea that even with the workforce that you have, you should regularly rank them and cull the bottom what, 10%, right?

GELLES: He had a euphemistic name for this practice. He called it the vitality curve, but it was known internally and more broadly in the public as stack ranking or, even more sharply, rank and yank. And the idea is this. Managers, he said, needed to rank their employees. Twenty percent get an A grade. Seventy percent get a B grade, and 10% get a C grade. And if you're in that 10%, you're out of the company. He did that for 20 years inside GE, which led to thousands and thousands of layoffs. And it became, because he was so influential, dogma in corporate America.”

From NPR’s Fresh Air: https://freshairarchive.org/segments/short-term-profits-and-long-term-consequences-did-jack-welch-break-capitalism