-97.71% is the change from 656 to 15
Calculation steps:
[( 15 - 656 ) ÷ 656] x 100 = -97.71%
Formula
Percentage change = [(15 - 656) / 656] x 100
Subtract the new number by the original number
15 - 656 = -641
-641 ÷ 656 = -0.9771341463414634
-0.9771341463414634 x 100 = -97.71%