-10% is the change from 680 to 612
Calculation steps:
[( 612 - 680 ) ÷ 680] x 100 = -10%
Formula
Percentage change = [(612 - 680) / 680] x 100
Subtract the new number by the original number
612 - 680 = -68
-68 ÷ 680 = -0.1
-0.1 x 100 = -10%
Example