-91.55% is the change from 639 to 54
Calculation steps:
[( 54 - 639 ) ÷ 639] x 100 = -91.55%
Formula
Percentage change = [(54 - 639) / 639] x 100
Subtract the new number by the original number
54 - 639 = -585
-585 ÷ 639 = -0.9154929577464789
-0.9154929577464789 x 100 = -91.55%