-72.5% is the change from 240 to 66
Calculation steps:
[( 66 - 240 ) ÷ 240] x 100 = -72.5%
Formula
Percentage change = [(66 - 240) / 240] x 100
Subtract the new number by the original number
66 - 240 = -174
-174 ÷ 240 = -0.725
-0.725 x 100 = -72.5%
Example