-74.71% is the change from 850 to 215
Calculation steps:
[( 215 - 850 ) ÷ 850] x 100 = -74.71%
Formula
Percentage change = [(215 - 850) / 850] x 100
Subtract the new number by the original number
215 - 850 = -635
-635 ÷ 850 = -0.7470588235294118
-0.7470588235294118 x 100 = -74.71%