-51.5% is the change from 668 to 324
Calculation steps:
[( 324 - 668 ) ÷ 668] x 100 = -51.5%
Formula
Percentage change = [(324 - 668) / 668] x 100
Subtract the new number by the original number
324 - 668 = -344
-344 ÷ 668 = -0.5149700598802395
-0.5149700598802395 x 100 = -51.5%