-77.31% is the change from 639 to 145
Calculation steps:
[( 145 - 639 ) ÷ 639] x 100 = -77.31%
Formula
Percentage change = [(145 - 639) / 639] x 100
Subtract the new number by the original number
145 - 639 = -494
-494 ÷ 639 = -0.7730829420970265
-0.7730829420970265 x 100 = -77.31%