-83.78% is the change from 666 to 108
Calculation steps:
[( 108 - 666 ) ÷ 666] x 100 = -83.78%
Formula
Percentage change = [(108 - 666) / 666] x 100
Subtract the new number by the original number
108 - 666 = -558
-558 ÷ 666 = -0.8378378378378378
-0.8378378378378378 x 100 = -83.78%