-49.51% is the change from 507 to 256
Calculation steps:
[( 256 - 507 ) ÷ 507] x 100 = -49.51%
Formula
Percentage change = [(256 - 507) / 507] x 100
Subtract the new number by the original number
256 - 507 = -251
-251 ÷ 507 = -0.49506903353057197
-0.49506903353057197 x 100 = -49.51%