-89.63% is the change from 820 to 85
Calculation steps:
[( 85 - 820 ) ÷ 820] x 100 = -89.63%
Formula
Percentage change = [(85 - 820) / 820] x 100
Subtract the new number by the original number
85 - 820 = -735
-735 ÷ 820 = -0.8963414634146342
-0.8963414634146342 x 100 = -89.63%