-89.88% is the change from 850 to 86
Calculation steps:
[( 86 - 850 ) ÷ 850] x 100 = -89.88%
Formula
Percentage change = [(86 - 850) / 850] x 100
Subtract the new number by the original number
86 - 850 = -764
-764 ÷ 850 = -0.8988235294117647
-0.8988235294117647 x 100 = -89.88%