-84.33% is the change from 638 to 100
Calculation steps:
[( 100 - 638 ) ÷ 638] x 100 = -84.33%
Formula
Percentage change = [(100 - 638) / 638] x 100
Subtract the new number by the original number
100 - 638 = -538
-538 ÷ 638 = -0.8432601880877743
-0.8432601880877743 x 100 = -84.33%