-97.2% is the change from 644 to 18
Calculation steps:
[( 18 - 644 ) ÷ 644] x 100 = -97.2%
Formula
Percentage change = [(18 - 644) / 644] x 100
Subtract the new number by the original number
18 - 644 = -626
-626 ÷ 644 = -0.9720496894409938
-0.9720496894409938 x 100 = -97.2%