840.91% is the change from 66 to 621
Calculation steps:
[( 621 - 66 ) ÷ 66] x 100 = 840.91%
Formula
Percentage change = [(621 - 66) / 66] x 100
Subtract the new number by the original number
621 - 66 = 555
555 ÷ 66 = 8.409090909090908
8.409090909090908 x 100 = 840.91%