-97.72% is the change from 657 to 15
Calculation steps:
[( 15 - 657 ) ÷ 657] x 100 = -97.72%
Formula
Percentage change = [(15 - 657) / 657] x 100
Subtract the new number by the original number
15 - 657 = -642
-642 ÷ 657 = -0.9771689497716894
-0.9771689497716894 x 100 = -97.72%