-33.3% is the change from 958 to 639
Calculation steps:
[( 639 - 958 ) ÷ 958] x 100 = -33.3%
Formula
Percentage change = [(639 - 958) / 958] x 100
Subtract the new number by the original number
639 - 958 = -319
-319 ÷ 958 = -0.33298538622129437
-0.33298538622129437 x 100 = -33.3%