-39.81% is the change from 643 to 387
Calculation steps:
[( 387 - 643 ) ÷ 643] x 100 = -39.81%
Formula
Percentage change = [(387 - 643) / 643] x 100
Subtract the new number by the original number
387 - 643 = -256
-256 ÷ 643 = -0.39813374805598756
-0.39813374805598756 x 100 = -39.81%