-13.21% is the change from 939 to 815
Calculation steps:
[( 815 - 939 ) ÷ 939] x 100 = -13.21%
Formula
Percentage change = [(815 - 939) / 939] x 100
Subtract the new number by the original number
815 - 939 = -124
-124 ÷ 939 = -0.13205537806176784
-0.13205537806176784 x 100 = -13.21%