-99.4% is the change from 502 to 3
Calculation steps:
[( 3 - 502 ) ÷ 502] x 100 = -99.4%
Formula
Percentage change = [(3 - 502) / 502] x 100
Subtract the new number by the original number
3 - 502 = -499
-499 ÷ 502 = -0.9940239043824701
-0.9940239043824701 x 100 = -99.4%