-50.63% is the change from 79 to 39
Calculation steps:
[( 39 - 79 ) ÷ 79] x 100 = -50.63%
Formula
Percentage change = [(39 - 79) / 79] x 100
Subtract the new number by the original number
39 - 79 = -40
-40 ÷ 79 = -0.5063291139240507
-0.5063291139240507 x 100 = -50.63%