-79.75% is the change from 489 to 99
Calculation steps:
[( 99 - 489 ) ÷ 489] x 100 = -79.75%
Formula
Percentage change = [(99 - 489) / 489] x 100
Subtract the new number by the original number
99 - 489 = -390
-390 ÷ 489 = -0.7975460122699386
-0.7975460122699386 x 100 = -79.75%