-30.84% is the change from 924 to 639
Calculation steps:
[( 639 - 924 ) ÷ 924] x 100 = -30.84%
Formula
Percentage change = [(639 - 924) / 924] x 100
Subtract the new number by the original number
639 - 924 = -285
-285 ÷ 924 = -0.30844155844155846
-0.30844155844155846 x 100 = -30.84%