-30.43% is the change from 917 to 638
Calculation steps:
[( 638 - 917 ) ÷ 917] x 100 = -30.43%
Formula
Percentage change = [(638 - 917) / 917] x 100
Subtract the new number by the original number
638 - 917 = -279
-279 ÷ 917 = -0.3042529989094875
-0.3042529989094875 x 100 = -30.43%