-90.01% is the change from 811 to 81
Calculation steps:
[( 81 - 811 ) ÷ 811] x 100 = -90.01%
Formula
Percentage change = [(81 - 811) / 811] x 100
Subtract the new number by the original number
81 - 811 = -730
-730 ÷ 811 = -0.9001233045622689
-0.9001233045622689 x 100 = -90.01%