-98.8% is the change from 668 to 8
Calculation steps:
[( 8 - 668 ) ÷ 668] x 100 = -98.8%
Formula
Percentage change = [(8 - 668) / 668] x 100
Subtract the new number by the original number
8 - 668 = -660
-660 ÷ 668 = -0.9880239520958084
-0.9880239520958084 x 100 = -98.8%