-40.35% is the change from 513 to 306
Calculation steps:
[( 306 - 513 ) ÷ 513] x 100 = -40.35%
Formula
Percentage change = [(306 - 513) / 513] x 100
Subtract the new number by the original number
306 - 513 = -207
-207 ÷ 513 = -0.40350877192982454
-0.40350877192982454 x 100 = -40.35%