-89.46% is the change from 939 to 99
Calculation steps:
[( 99 - 939 ) ÷ 939] x 100 = -89.46%
Formula
Percentage change = [(99 - 939) / 939] x 100
Subtract the new number by the original number
99 - 939 = -840
-840 ÷ 939 = -0.8945686900958466
-0.8945686900958466 x 100 = -89.46%