645.56% is the change from 90 to 671
Calculation steps:
[( 671 - 90 ) ÷ 90] x 100 = 645.56%
Formula
Percentage change = [(671 - 90) / 90] x 100
Subtract the new number by the original number
671 - 90 = 581
581 ÷ 90 = 6.455555555555556
6.455555555555556 x 100 = 645.56%