660% is the change from 90 to 684
Calculation steps:
[( 684 - 90 ) ÷ 90] x 100 = 660%
Formula
Percentage change = [(684 - 90) / 90] x 100
Subtract the new number by the original number
684 - 90 = 594
594 ÷ 90 = 6.6
6.6 x 100 = 660%
Example