Do you have a field that determines the sort order? A date or serial number or perhaps text that needs to be sorted alphabetically?
If you have something like that you can use a counting query. The sql looks like this:
SELECT p.KeyPct, (SELECT COUNT(*) FROM tblMiscPct WHERE KeyPct >= p.KeyPct) AS Rank
FROM tblMiscPct AS p
ORDER BY p.KeyPct DESC;
THere we rank a set of records by a percent field. By counting records with an equal or greater value than the current record we come up with a "ranking" or "row" number.
There can be ties, so the ORDER BY becomes more important.
If you post more info on your needs someone will provide more exact help.