-39.91% is the change from 664 to 399
Calculation steps:
[( 399 - 664 ) ÷ 664] x 100 = -39.91%
Formula
Percentage change = [(399 - 664) / 664] x 100
Subtract the new number by the original number
399 - 664 = -265
-265 ÷ 664 = -0.3990963855421687
-0.3990963855421687 x 100 = -39.91%