-6.17% is the change from 681 to 639
Calculation steps:
[( 639 - 681 ) ÷ 681] x 100 = -6.17%
Formula
Percentage change = [(639 - 681) / 681] x 100
Subtract the new number by the original number
639 - 681 = -42
-42 ÷ 681 = -0.06167400881057269
-0.06167400881057269 x 100 = -6.17%