250% is the change from 66 to 231
Calculation steps:
[( 231 - 66 ) ÷ 66] x 100 = 250%
Formula
Percentage change = [(231 - 66) / 66] x 100
Subtract the new number by the original number
231 - 66 = 165
165 ÷ 66 = 2.5
2.5 x 100 = 250%
Example