-39.39% is the change from 990 to 600
Calculation steps:
[( 600 - 990 ) ÷ 990] x 100 = -39.39%
Formula
Percentage change = [(600 - 990) / 990] x 100
Subtract the new number by the original number
600 - 990 = -390
-390 ÷ 990 = -0.3939393939393939
-0.3939393939393939 x 100 = -39.39%