-50.6% is the change from 664 to 328
Calculation steps:
[( 328 - 664 ) ÷ 664] x 100 = -50.6%
Formula
Percentage change = [(328 - 664) / 664] x 100
Subtract the new number by the original number
328 - 664 = -336
-336 ÷ 664 = -0.5060240963855421
-0.5060240963855421 x 100 = -50.6%