339.39% is the change from 66 to 290
Calculation steps:
[( 290 - 66 ) ÷ 66] x 100 = 339.39%
Formula
Percentage change = [(290 - 66) / 66] x 100
Subtract the new number by the original number
290 - 66 = 224
224 ÷ 66 = 3.393939393939394
3.393939393939394 x 100 = 339.39%