-0.47% is the change from 641 to 638
Calculation steps:
[( 638 - 641 ) ÷ 641] x 100 = -0.47%
Formula
Percentage change = [(638 - 641) / 641] x 100
Subtract the new number by the original number
638 - 641 = -3
-3 ÷ 641 = -0.0046801872074883
-0.0046801872074883 x 100 = -0.47%