-2.21% is the change from 680 to 665
Calculation steps:
[( 665 - 680 ) ÷ 680] x 100 = -2.21%
Formula
Percentage change = [(665 - 680) / 680] x 100
Subtract the new number by the original number
665 - 680 = -15
-15 ÷ 680 = -0.022058823529411766
-0.022058823529411766 x 100 = -2.21%