-97.9% is the change from 666 to 14
Calculation steps:
[( 14 - 666 ) ÷ 666] x 100 = -97.9%
Formula
Percentage change = [(14 - 666) / 666] x 100
Subtract the new number by the original number
14 - 666 = -652
-652 ÷ 666 = -0.978978978978979
-0.978978978978979 x 100 = -97.9%