COLUMN object_name FORMAT A40
COLUMN number_of_blocks FORMAT 999,999,999,999
SELECT o.object_name, COUNT(*) number_of_blocks
  FROM DBA_OBJECTS o, V$BH bh
 WHERE o.data_object_id = bh.OBJD
   --AND o.owner != 'SYS'
 GROUP BY o.object_Name
 ORDER BY COUNT(*);