-80.63% is the change from 666 to 129
Calculation steps:
[( 129 - 666 ) ÷ 666] x 100 = -80.63%
Formula
Percentage change = [(129 - 666) / 666] x 100
Subtract the new number by the original number
129 - 666 = -537
-537 ÷ 666 = -0.8063063063063063
-0.8063063063063063 x 100 = -80.63%