-50.47% is the change from 636 to 315
Calculation steps:
[( 315 - 636 ) ÷ 636] x 100 = -50.47%
Formula
Percentage change = [(315 - 636) / 636] x 100
Subtract the new number by the original number
315 - 636 = -321
-321 ÷ 636 = -0.5047169811320755
-0.5047169811320755 x 100 = -50.47%