-31.72% is the change from 640 to 437
Calculation steps:
[( 437 - 640 ) ÷ 640] x 100 = -31.72%
Formula
Percentage change = [(437 - 640) / 640] x 100
Subtract the new number by the original number
437 - 640 = -203
-203 ÷ 640 = -0.3171875
-0.3171875 x 100 = -31.72%