Find buffer cache usage - oracle database script

col object_name format a30 col to_total format 999.99
SELECT OWNER,
       object_name,
       object_type,
       COUNT,
       (COUNT / value) * 100 to_total
FROM
  (SELECT a.owner,
          a.object_name,
          a.object_type,
          count(*) COUNT
   FROM dba_objects a,
        x$bh b
   WHERE a.object_id = b.obj
     AND a.owner NOT IN ('SYS',
                         'SYSTEM')
   GROUP BY a.owner,
            a.object_name,
            a.object_type
   ORDER BY 4), v$parameter
WHERE name = 'db_cache_size'
  AND (COUNT / value) * 100  .005
ORDER BY to_total DESC /