-39.64% is the change from 507 to 306
Calculation steps:
[( 306 - 507 ) ÷ 507] x 100 = -39.64%
Formula
Percentage change = [(306 - 507) / 507] x 100
Subtract the new number by the original number
306 - 507 = -201
-201 ÷ 507 = -0.39644970414201186
-0.39644970414201186 x 100 = -39.64%