In brief
In the American label, the values for one serving should be associated with the amount eaten.
Useful to know
On the American Nutrition Facts label, the information is usually presented for a specified portion. The FDA specifies that the serving size reflects a typically consumed amount and is not a recommendation on how much to eat. One pack may contain more than one serving. [1]
Conditional example: if 100 kcal is indicated for one portion and you eat two such portions, the corresponding amount is 200 kcal. It's arithmetic to read the label, not a dietary recommendation.
First look at the portion size and the number of portions, then read the numbers. If there is a separate column on the package for the entire package, do not multiply a value that is already common again. The text addresses the US format; does not present all labelling rules in the European Union and does not replace the guidelines of the specific product.
Sources
For further detail and to check the information: