Can I see Table I/O per month?
This will give you correct estimates only if you are sure that the server has not been restarted during the time frame you are intending to check..

--to check when server is last restarted

SELECT sqlserver_start_time FROM sys.dm_os_sys_info


--to see stats for  table

SELECT TableName = object_name(s.object_id),
       Reads = SUM(user_seeks + user_scans + user_lookups), Writes =  SUM(user_updates)
FROM sys.dm_db_index_usage_stats AS s
INNER JOIN sys.indexes AS i
ON s.object_id = i.object_id
AND i.index_id = s.index_id
WHERE objectproperty(s.object_id,'IsUserTable') = 1
GROUP BY object_name(s.object_id)
ORDER BY writes DESC


References:https://stackoverflow.com/questions/1575676/how-to-find-out-sql-server-tables-read-write-statistics