-40.58% is the change from 515 to 306
Calculation steps:
[( 306 - 515 ) ÷ 515] x 100 = -40.58%
Formula
Percentage change = [(306 - 515) / 515] x 100
Subtract the new number by the original number
306 - 515 = -209
-209 ÷ 515 = -0.4058252427184466
-0.4058252427184466 x 100 = -40.58%