-93.42% is the change from 638 to 42
Calculation steps:
[( 42 - 638 ) ÷ 638] x 100 = -93.42%
Formula
Percentage change = [(42 - 638) / 638] x 100
Subtract the new number by the original number
42 - 638 = -596
-596 ÷ 638 = -0.9341692789968652
-0.9341692789968652 x 100 = -93.42%