-31.55% is the change from 935 to 640
Calculation steps:
[( 640 - 935 ) ÷ 935] x 100 = -31.55%
Formula
Percentage change = [(640 - 935) / 935] x 100
Subtract the new number by the original number
640 - 935 = -295
-295 ÷ 935 = -0.3155080213903743
-0.3155080213903743 x 100 = -31.55%