ABC classifications - Margin meaning

Hi folks,

I gone through the ABC classifications manual in Axapta. But i could not understand the meaning of Margin.meaning of

Margin - Specify the item’s ABC code for marginal income. For example, if A is specified in this field, the selected item is categorized as an A Item, that makes up 20% of the total inventory and accounts for 80% of the total marginal income.

please share about this with a practical example.

ABC classifies the stock to enable you to count in different ways. This classification will categorise the items based upon the margin, the difference between cost and price, so rather than value or turnover it is done on margin (not sure if this is value or % so you would need to check).