-34.23% is the change from 970 to 638
Calculation steps:
[( 638 - 970 ) ÷ 970] x 100 = -34.23%
Formula
Percentage change = [(638 - 970) / 970] x 100
Subtract the new number by the original number
638 - 970 = -332
-332 ÷ 970 = -0.3422680412371134
-0.3422680412371134 x 100 = -34.23%