504.55% is the change from 66 to 399
Calculation steps:
[( 399 - 66 ) ÷ 66] x 100 = 504.55%
Formula
Percentage change = [(399 - 66) / 66] x 100
Subtract the new number by the original number
399 - 66 = 333
333 ÷ 66 = 5.045454545454546
5.045454545454546 x 100 = 504.55%