-1.34% is the change from 673 to 664
Calculation steps:
[( 664 - 673 ) ÷ 673] x 100 = -1.34%
Formula
Percentage change = [(664 - 673) / 673] x 100
Subtract the new number by the original number
664 - 673 = -9
-9 ÷ 673 = -0.01337295690936107
-0.01337295690936107 x 100 = -1.34%