-33.6% is the change from 509 to 338
Calculation steps:
[( 338 - 509 ) ÷ 509] x 100 = -33.6%
Formula
Percentage change = [(338 - 509) / 509] x 100
Subtract the new number by the original number
338 - 509 = -171
-171 ÷ 509 = -0.33595284872298625
-0.33595284872298625 x 100 = -33.6%