-85.18% is the change from 668 to 99
Calculation steps:
[( 99 - 668 ) ÷ 668] x 100 = -85.18%
Formula
Percentage change = [(99 - 668) / 668] x 100
Subtract the new number by the original number
99 - 668 = -569
-569 ÷ 668 = -0.8517964071856288
-0.8517964071856288 x 100 = -85.18%