-21.27% is the change from 818 to 644
Calculation steps:
[( 644 - 818 ) ÷ 818] x 100 = -21.27%
Formula
Percentage change = [(644 - 818) / 818] x 100
Subtract the new number by the original number
644 - 818 = -174
-174 ÷ 818 = -0.21271393643031786
-0.21271393643031786 x 100 = -21.27%