-3.51% is the change from 684 to 660
Calculation steps:
[( 660 - 684 ) ÷ 684] x 100 = -3.51%
Formula
Percentage change = [(660 - 684) / 684] x 100
Subtract the new number by the original number
660 - 684 = -24
-24 ÷ 684 = -0.03508771929824561
-0.03508771929824561 x 100 = -3.51%