-3.99% is the change from 978 to 939
Calculation steps:
[( 939 - 978 ) ÷ 978] x 100 = -3.99%
Formula
Percentage change = [(939 - 978) / 978] x 100
Subtract the new number by the original number
939 - 978 = -39
-39 ÷ 978 = -0.03987730061349693
-0.03987730061349693 x 100 = -3.99%