-98.5% is the change from 668 to 10
Calculation steps:
[( 10 - 668 ) ÷ 668] x 100 = -98.5%
Formula
Percentage change = [(10 - 668) / 668] x 100
Subtract the new number by the original number
10 - 668 = -658
-658 ÷ 668 = -0.9850299401197605
-0.9850299401197605 x 100 = -98.5%