Labeling duplicates

I used conditional formatting to highlight the duplicates (they are highlighted in red).
The unique entries need to be marked with a 1. The duplicate groups need to be marked
1,2,3,4,etc... (column H) with the most recent one on top.
(the spreadsheet is already sorted by column E). Any suggestions on how to do this?

Use the COUNTIF formula that only counts the rows above. See attached.

NEW FORMAT v2.xlsx

Thank you. This worked great!