How to find the average of an Int Field

Need help producing the average of an int field, specifically number of days on average a delivery is late for a vendor.
I have the number of days that each delivery is late calculated and populating in its own field (late days).
This new field will be at the bottom of this report where all the totals are for each vendor giving the average days late that vendor is in regards to its delivery’s.

This is for the Vendor (or Supplier) on Time Delivery report.

Is it about an SSRS report? If so, you can use an expression with Avg() function.

Hi Martin,
Yes this is one of the out of the box reports in D365. Would you be able to provide a practical example of the avg() function being used.

Thanks
Joe S.