-50.2% is the change from 502 to 250
Calculation steps:
[( 250 - 502 ) ÷ 502] x 100 = -50.2%
Formula
Percentage change = [(250 - 502) / 502] x 100
Subtract the new number by the original number
250 - 502 = -252
-252 ÷ 502 = -0.50199203187251
-0.50199203187251 x 100 = -50.2%