-3.88% is the change from 670 to 644
Calculation steps:
[( 644 - 670 ) ÷ 670] x 100 = -3.88%
Formula
Percentage change = [(644 - 670) / 670] x 100
Subtract the new number by the original number
644 - 670 = -26
-26 ÷ 670 = -0.03880597014925373
-0.03880597014925373 x 100 = -3.88%