-85.45% is the change from 639 to 93
Calculation steps:
[( 93 - 639 ) ÷ 639] x 100 = -85.45%
Formula
Percentage change = [(93 - 639) / 639] x 100
Subtract the new number by the original number
93 - 639 = -546
-546 ÷ 639 = -0.8544600938967136
-0.8544600938967136 x 100 = -85.45%