-40.46% is the change from 519 to 309
Calculation steps:
[( 309 - 519 ) ÷ 519] x 100 = -40.46%
Formula
Percentage change = [(309 - 519) / 519] x 100
Subtract the new number by the original number
309 - 519 = -210
-210 ÷ 519 = -0.4046242774566474
-0.4046242774566474 x 100 = -40.46%