289.39% is the change from 66 to 257
Calculation steps:
[( 257 - 66 ) ÷ 66] x 100 = 289.39%
Formula
Percentage change = [(257 - 66) / 66] x 100
Subtract the new number by the original number
257 - 66 = 191
191 ÷ 66 = 2.893939393939394
2.893939393939394 x 100 = 289.39%