-31.3% is the change from 639 to 439
Calculation steps:
[( 439 - 639 ) ÷ 639] x 100 = -31.3%
Formula
Percentage change = [(439 - 639) / 639] x 100
Subtract the new number by the original number
439 - 639 = -200
-200 ÷ 639 = -0.3129890453834116
-0.3129890453834116 x 100 = -31.3%