-98.59% is the change from 637 to 9
Calculation steps:
[( 9 - 637 ) ÷ 637] x 100 = -98.59%
Formula
Percentage change = [(9 - 637) / 637] x 100
Subtract the new number by the original number
9 - 637 = -628
-628 ÷ 637 = -0.9858712715855573
-0.9858712715855573 x 100 = -98.59%