I have a report that sorts stores by thier sales performance. Is report is ran daily and the rankings change from day to day. What I need to do is add in a textbox to the report that will autonumber the stores and they are sorted. The number of store will change monthly. Any ideas?

Ensure the records are ordered as you wish.

Create a Text Box in the header or footer of the item you wish to rank, eg in the [StoreID] header.

Set the ControlSource of the Text Box to:
=Count([StoreID])

This will only count one store per header. However, if you set the RunningSum property of the Text Box to "Over All", this will act as a counter, incrementing by one for each new header.

Hope this helps
Cheers
Tony