Marking Up Latest Occurence In 2003

I am looking at a register of documents that are constantly being revised. What I need to do is mark up which ones need to be reviewedDocument RevisionViewedapples1apples2yapples3apples4apples5pears1pears2ypears3pears4oranges1oranges2oranges3

If a revision is marked as Y then previous revisions don;t need to be looked at and can be marked with n/a anything older doesn't need to be reviewed except for the latest one. In the above table if apples revision 2 has been viewed so rev 1, 3, and 4 are no longer relevant and only rev 5 needs to be reviewed. Pears rev 2 has been reviewed so on rev 4 needs to be reviewed. No Orange documents have been reviewed so only rev 3 needs to be reviewed.

The above is just an example my table consists of 8000 entries.