-6.03% is the change from 680 to 639
Calculation steps:
[( 639 - 680 ) ÷ 680] x 100 = -6.03%
Formula
Percentage change = [(639 - 680) / 680] x 100
Subtract the new number by the original number
639 - 680 = -41
-41 ÷ 680 = -0.060294117647058824
-0.060294117647058824 x 100 = -6.03%