-89.51% is the change from 820 to 86
Calculation steps:
[( 86 - 820 ) ÷ 820] x 100 = -89.51%
Formula
Percentage change = [(86 - 820) / 820] x 100
Subtract the new number by the original number
86 - 820 = -734
-734 ÷ 820 = -0.8951219512195122
-0.8951219512195122 x 100 = -89.51%