-75.29% is the change from 850 to 210
Calculation steps:
[( 210 - 850 ) ÷ 850] x 100 = -75.29%
Formula
Percentage change = [(210 - 850) / 850] x 100
Subtract the new number by the original number
210 - 850 = -640
-640 ÷ 850 = -0.7529411764705882
-0.7529411764705882 x 100 = -75.29%