-20.59% is the change from 680 to 540
Calculation steps:
[( 540 - 680 ) ÷ 680] x 100 = -20.59%
Formula
Percentage change = [(540 - 680) / 680] x 100
Subtract the new number by the original number
540 - 680 = -140
-140 ÷ 680 = -0.20588235294117646
-0.20588235294117646 x 100 = -20.59%