-9.73% is the change from 709 to 640
Calculation steps:
[( 640 - 709 ) ÷ 709] x 100 = -9.73%
Formula
Percentage change = [(640 - 709) / 709] x 100
Subtract the new number by the original number
640 - 709 = -69
-69 ÷ 709 = -0.09732016925246827
-0.09732016925246827 x 100 = -9.73%