-34.29% is the change from 971 to 638
Calculation steps:
[( 638 - 971 ) ÷ 971] x 100 = -34.29%
Formula
Percentage change = [(638 - 971) / 971] x 100
Subtract the new number by the original number
638 - 971 = -333
-333 ÷ 971 = -0.3429454170957775
-0.3429454170957775 x 100 = -34.29%