-83.49% is the change from 939 to 155
Calculation steps:
[( 155 - 939 ) ÷ 939] x 100 = -83.49%
Formula
Percentage change = [(155 - 939) / 939] x 100
Subtract the new number by the original number
155 - 939 = -784
-784 ÷ 939 = -0.8349307774227902
-0.8349307774227902 x 100 = -83.49%