-79.76% is the change from 850 to 172
Calculation steps:
[( 172 - 850 ) ÷ 850] x 100 = -79.76%
Formula
Percentage change = [(172 - 850) / 850] x 100
Subtract the new number by the original number
172 - 850 = -678
-678 ÷ 850 = -0.7976470588235294
-0.7976470588235294 x 100 = -79.76%