-9.62% is the change from 686 to 620
Calculation steps:
[( 620 - 686 ) ÷ 686] x 100 = -9.62%
Formula
Percentage change = [(620 - 686) / 686] x 100
Subtract the new number by the original number
620 - 686 = -66
-66 ÷ 686 = -0.09620991253644315
-0.09620991253644315 x 100 = -9.62%