If I am understanding your question correctly, you are wanting to identify which Forms processes had submissions in the last year.

Of course, you can get a lot of info out of the system using the Monitor or Reports pages.  If you don't have very many different processes, that's probably sufficient.  But if you have a lot of different processes (Dozens, Hundreds, or even Thousands), that could be problematic, since there isn't a easy way to see those kinds of statistics across the board.

In order to get an across the board look at your processes, I would run a query on the database like this: 

SELECT 
  bp.name,
  bp.date_created,
  COUNT(i.bp_instance_id) AS number_instances,
  MAX(i.bp_instance_id) AS highest_instance_id,
  MIN(i.start_date) AS earliest_start_date,
  MAX(i.start_date) AS latest_start_date
FROM cf_business_processes AS bp
LEFT JOIN cf_bp_processes AS bpp ON bpp.bp_id = bp.bp_id
LEFT JOIN cf_bp_main_instances AS i ON i.process_id = bpp.process_id AND i.start_date >= DATEADD(YEAR,-1,GETDATE())
WHERE bp.is_deleted = 0
  AND bpp.parent_process_id IS NULL
GROUP BY bp.name, bp.date_created

This query looks at all non-deleted processes, and them joins to the actual instances over the last 1 year (on or after 1 year prior to current date) and gives you a count (and some other values) of those instances over the last year.