-69.88% is the change from 850 to 256
Calculation steps:
[( 256 - 850 ) ÷ 850] x 100 = -69.88%
Formula
Percentage change = [(256 - 850) / 850] x 100
Subtract the new number by the original number
256 - 850 = -594
-594 ÷ 850 = -0.6988235294117647
-0.6988235294117647 x 100 = -69.88%