-83.76% is the change from 850 to 138
Calculation steps:
[( 138 - 850 ) ÷ 850] x 100 = -83.76%
Formula
Percentage change = [(138 - 850) / 850] x 100
Subtract the new number by the original number
138 - 850 = -712
-712 ÷ 850 = -0.8376470588235294
-0.8376470588235294 x 100 = -83.76%