-84.28% is the change from 509 to 80
Calculation steps:
[( 80 - 509 ) ÷ 509] x 100 = -84.28%
Formula
Percentage change = [(80 - 509) / 509] x 100
Subtract the new number by the original number
80 - 509 = -429
-429 ÷ 509 = -0.8428290766208252
-0.8428290766208252 x 100 = -84.28%