-21.41% is the change from 850 to 668
Calculation steps:
[( 668 - 850 ) ÷ 850] x 100 = -21.41%
Formula
Percentage change = [(668 - 850) / 850] x 100
Subtract the new number by the original number
668 - 850 = -182
-182 ÷ 850 = -0.21411764705882352
-0.21411764705882352 x 100 = -21.41%