-50.39% is the change from 637 to 316
Calculation steps:
[( 316 - 637 ) ÷ 637] x 100 = -50.39%
Formula
Percentage change = [(316 - 637) / 637] x 100
Subtract the new number by the original number
316 - 637 = -321
-321 ÷ 637 = -0.5039246467817896
-0.5039246467817896 x 100 = -50.39%