-91.76% is the change from 850 to 70
Calculation steps:
[( 70 - 850 ) ÷ 850] x 100 = -91.76%
Formula
Percentage change = [(70 - 850) / 850] x 100
Subtract the new number by the original number
70 - 850 = -780
-780 ÷ 850 = -0.9176470588235294
-0.9176470588235294 x 100 = -91.76%