-23.48% is the change from 660 to 505
Calculation steps:
[( 505 - 660 ) ÷ 660] x 100 = -23.48%
Formula
Percentage change = [(505 - 660) / 660] x 100
Subtract the new number by the original number
505 - 660 = -155
-155 ÷ 660 = -0.23484848484848486
-0.23484848484848486 x 100 = -23.48%