-3.16% is the change from 665 to 644
Calculation steps:
[( 644 - 665 ) ÷ 665] x 100 = -3.16%
Formula
Percentage change = [(644 - 665) / 665] x 100
Subtract the new number by the original number
644 - 665 = -21
-21 ÷ 665 = -0.031578947368421054
-0.031578947368421054 x 100 = -3.16%