-89.55% is the change from 871 to 91
Calculation steps:
[( 91 - 871 ) ÷ 871] x 100 = -89.55%
Formula
Percentage change = [(91 - 871) / 871] x 100
Subtract the new number by the original number
91 - 871 = -780
-780 ÷ 871 = -0.8955223880597015
-0.8955223880597015 x 100 = -89.55%