Formula for counting Occurences when Multiple entries for the same DOB and Service Date

I was asked to help come up with a way to have a running count of an individual who visits a hospital or clinic. There are more than one entry per person due to multiple payments from insurance that must be tracked. However, they need to take random samples and need each occurrence to have a number in order of the entry to the spreadsheet. We can do this by filtering the data by DOB and then by Date of Visit, but they would prefer to have on the original data a column, say column A, that numbers each occurrence. Any suggestions?

Thank you! I am a first time poster and appreciate any insight!

Attach a sample workbook. Make sure there is just enough data to demonstrate your need. Include a BEFORE sheet and an AFTER sheet in the workbook if needed to show the process you're trying to complete or automate. Make sure your desired results are shown, mock them up manually if necessary.

Remember to desensitize the data.

Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.