-75.15% is the change from 668 to 166
Calculation steps:
[( 166 - 668 ) ÷ 668] x 100 = -75.15%
Formula
Percentage change = [(166 - 668) / 668] x 100
Subtract the new number by the original number
166 - 668 = -502
-502 ÷ 668 = -0.7514970059880239
-0.7514970059880239 x 100 = -75.15%