-75.29% is the change from 85 to 21
Calculation steps:
[( 21 - 85 ) ÷ 85] x 100 = -75.29%
Formula
Percentage change = [(21 - 85) / 85] x 100
Subtract the new number by the original number
21 - 85 = -64
-64 ÷ 85 = -0.7529411764705882
-0.7529411764705882 x 100 = -75.29%