-33.16% is the change from 956 to 639
Calculation steps:
[( 639 - 956 ) ÷ 956] x 100 = -33.16%
Formula
Percentage change = [(639 - 956) / 956] x 100
Subtract the new number by the original number
639 - 956 = -317
-317 ÷ 956 = -0.33158995815899583
-0.33158995815899583 x 100 = -33.16%