-78.87% is the change from 639 to 135
Calculation steps:
[( 135 - 639 ) ÷ 639] x 100 = -78.87%
Formula
Percentage change = [(135 - 639) / 639] x 100
Subtract the new number by the original number
135 - 639 = -504
-504 ÷ 639 = -0.7887323943661971
-0.7887323943661971 x 100 = -78.87%