-96.86% is the change from 668 to 21
Calculation steps:
[( 21 - 668 ) ÷ 668] x 100 = -96.86%
Formula
Percentage change = [(21 - 668) / 668] x 100
Subtract the new number by the original number
21 - 668 = -647
-647 ÷ 668 = -0.968562874251497
-0.968562874251497 x 100 = -96.86%