-79.79% is the change from 668 to 135
Calculation steps:
[( 135 - 668 ) ÷ 668] x 100 = -79.79%
Formula
Percentage change = [(135 - 668) / 668] x 100
Subtract the new number by the original number
135 - 668 = -533
-533 ÷ 668 = -0.7979041916167665
-0.7979041916167665 x 100 = -79.79%