-2.79% is the change from 680 to 661
Calculation steps:
[( 661 - 680 ) ÷ 680] x 100 = -2.79%
Formula
Percentage change = [(661 - 680) / 680] x 100
Subtract the new number by the original number
661 - 680 = -19
-19 ÷ 680 = -0.027941176470588237
-0.027941176470588237 x 100 = -2.79%