-50.1% is the change from 499 to 249
Calculation steps:
[( 249 - 499 ) ÷ 499] x 100 = -50.1%
Formula
Percentage change = [(249 - 499) / 499] x 100
Subtract the new number by the original number
249 - 499 = -250
-250 ÷ 499 = -0.501002004008016
-0.501002004008016 x 100 = -50.1%