What does impression share indicate about a product group?

It shows your product group impressions relative to other product groups in the same campaign
It provides an average benchmark of all similar products from other retailers
It predicts your product group’s future impressions
It shows how many impressions your product group has received divided by the estimated number it was eligible to receive

The correct answer is:

It shows how many impressions your product group has received divided by the estimated number it was eligible to receive.