-89.01% is the change from 91 to 10
Calculation steps:
[( 10 - 91 ) ÷ 91] x 100 = -89.01%
Formula
Percentage change = [(10 - 91) / 91] x 100
Subtract the new number by the original number
10 - 91 = -81
-81 ÷ 91 = -0.8901098901098901
-0.8901098901098901 x 100 = -89.01%