-85.89% is the change from 638 to 90
Calculation steps:
[( 90 - 638 ) ÷ 638] x 100 = -85.89%
Formula
Percentage change = [(90 - 638) / 638] x 100
Subtract the new number by the original number
90 - 638 = -548
-548 ÷ 638 = -0.8589341692789969
-0.8589341692789969 x 100 = -85.89%