-87.72% is the change from 668 to 82
Calculation steps:
[( 82 - 668 ) ÷ 668] x 100 = -87.72%
Formula
Percentage change = [(82 - 668) / 668] x 100
Subtract the new number by the original number
82 - 668 = -586
-586 ÷ 668 = -0.8772455089820359
-0.8772455089820359 x 100 = -87.72%