-99.8% is the change from 508 to 1
Calculation steps:
[( 1 - 508 ) ÷ 508] x 100 = -99.8%
Formula
Percentage change = [(1 - 508) / 508] x 100
Subtract the new number by the original number
1 - 508 = -507
-507 ÷ 508 = -0.9980314960629921
-0.9980314960629921 x 100 = -99.8%