-0.31% is the change from 650 to 648
Calculation steps:
[( 648 - 650 ) ÷ 650] x 100 = -0.31%
Formula
Percentage change = [(648 - 650) / 650] x 100
Subtract the new number by the original number
648 - 650 = -2
-2 ÷ 650 = -0.003076923076923077
-0.003076923076923077 x 100 = -0.31%