-17.25% is the change from 771 to 638
Calculation steps:
[( 638 - 771 ) ÷ 771] x 100 = -17.25%
Formula
Percentage change = [(638 - 771) / 771] x 100
Subtract the new number by the original number
638 - 771 = -133
-133 ÷ 771 = -0.17250324254215305
-0.17250324254215305 x 100 = -17.25%