-67.72% is the change from 666 to 215
Calculation steps:
[( 215 - 666 ) ÷ 666] x 100 = -67.72%
Formula
Percentage change = [(215 - 666) / 666] x 100
Subtract the new number by the original number
215 - 666 = -451
-451 ÷ 666 = -0.6771771771771772
-0.6771771771771772 x 100 = -67.72%