-81.84% is the change from 501 to 91
Calculation steps:
[( 91 - 501 ) ÷ 501] x 100 = -81.84%
Formula
Percentage change = [(91 - 501) / 501] x 100
Subtract the new number by the original number
91 - 501 = -410
-410 ÷ 501 = -0.8183632734530938
-0.8183632734530938 x 100 = -81.84%