-39.49% is the change from 509 to 308
Calculation steps:
[( 308 - 509 ) ÷ 509] x 100 = -39.49%
Formula
Percentage change = [(308 - 509) / 509] x 100
Subtract the new number by the original number
308 - 509 = -201
-201 ÷ 509 = -0.3948919449901768
-0.3948919449901768 x 100 = -39.49%