Sequential Numbering of Records in Access Report

I want to be able to number sequential the records in a report I have created. (I am using my autoincrementing field in my table for another purpose).

I understand I'm supposed to be able to do this by creating an unbound textbox, setting the control source =1 and setting the runningsum to Over Group or Over All.

However, I've tried that and it works for the first two records and then all the subsequent records are numbered "2". Can anyone tell me what I am doing wrong?

Found a working solution. If I put the textbox in the detail section it will number the records sequentially.

However the record number only appears on the first page of each record. I was hoping to use it as a page header, so every page had a reference to the record number