-1.54% is the change from 648 to 638
Calculation steps:
[( 638 - 648 ) ÷ 648] x 100 = -1.54%
Formula
Percentage change = [(638 - 648) / 648] x 100
Subtract the new number by the original number
638 - 648 = -10
-10 ÷ 648 = -0.015432098765432098
-0.015432098765432098 x 100 = -1.54%