Didn't know that!
The UK had 91% tax from 1945 - 1963
https://www.wolterskluwer.com/en/expert-insights/whole-ball-of-tax-historical-income-tax-rates
Discussion
But it’s not normally 90% of everything.
It’s normally (for example):
First 12K - no tax,
next 13K - 20% tax
next 50K - 40% tax
next 50K - 50% tax
anything above that 90% tax