-88.77% is the change from 810 to 91
Calculation steps:
[( 91 - 810 ) ÷ 810] x 100 = -88.77%
Formula
Percentage change = [(91 - 810) / 810] x 100
Subtract the new number by the original number
91 - 810 = -719
-719 ÷ 810 = -0.8876543209876543
-0.8876543209876543 x 100 = -88.77%