-89.88% is the change from 978 to 99
Calculation steps:
[( 99 - 978 ) ÷ 978] x 100 = -89.88%
Formula
Percentage change = [(99 - 978) / 978] x 100
Subtract the new number by the original number
99 - 978 = -879
-879 ÷ 978 = -0.8987730061349694
-0.8987730061349694 x 100 = -89.88%