-79.58% is the change from 666 to 136
Calculation steps:
[( 136 - 666 ) ÷ 666] x 100 = -79.58%
Formula
Percentage change = [(136 - 666) / 666] x 100
Subtract the new number by the original number
136 - 666 = -530
-530 ÷ 666 = -0.7957957957957958
-0.7957957957957958 x 100 = -79.58%