-96.86% is the change from 669 to 21
Calculation steps:
[( 21 - 669 ) ÷ 669] x 100 = -96.86%
Formula
Percentage change = [(21 - 669) / 669] x 100
Subtract the new number by the original number
21 - 669 = -648
-648 ÷ 669 = -0.968609865470852
-0.968609865470852 x 100 = -96.86%