-98.21% is the change from 502 to 9
Calculation steps:
[( 9 - 502 ) ÷ 502] x 100 = -98.21%
Formula
Percentage change = [(9 - 502) / 502] x 100
Subtract the new number by the original number
9 - 502 = -493
-493 ÷ 502 = -0.9820717131474104
-0.9820717131474104 x 100 = -98.21%