-38.9% is the change from 509 to 311
Calculation steps:
[( 311 - 509 ) ÷ 509] x 100 = -38.9%
Formula
Percentage change = [(311 - 509) / 509] x 100
Subtract the new number by the original number
311 - 509 = -198
-198 ÷ 509 = -0.3889980353634578
-0.3889980353634578 x 100 = -38.9%