espaço total gasto pelos segmentos

Pessoal fiz da forma abaixo mas a saida nao está correta ainda o percentual está errado.

	SELECT owner, 

	 data_mb, 

	 indx_mb, 

	 lob_mb, 

	 total_mb,

	 ratio_to_report(total_mb) over () AS RR

	 FROM (SELECT data.owner, 

	 NVL(data_mb,0) data_mb, 

	 NVL(indx_mb,0) indx_mb, 

	 NVL(lob_mb,0) lob_mb, 

	 NVL(data_mb,0) + NVL(indx_mb,0) + NVL(lob_mb,0) total_mb 

	 FROM ( SELECT owner, 

	 ROUND(SUM(data_mb),2) data_mb 

	 FROM (SELECT owner, data_mb 

	 FROM (SELECT a.owner, 

	 b.bytes/1024/1024 AS data_mb 

	 FROM dba_tables a, dba_segments b 

	 WHERE a.owner = b.owner and a.table_name = b.segment_name)) 

	 GROUP BY owner) data, 

	 ( SELECT a.owner, 

	 ROUND(SUM(b.bytes/1024/1024),2) AS indx_mb 

	 FROM dba_indexes a, dba_segments b 

	 WHERE a.owner = b.owner and a.index_name = b.segment_name 

	 GROUP BY a.owner) indx, 

	 ( SELECT a.owner, 

	 ROUND(SUM(b.bytes/1024/1024),2) AS lob_mb 

	 FROM dba_lobs a, dba_segments b 

	 WHERE a.owner = b.owner and a.segment_name = b.segment_name 

	 GROUP BY a.owner) lob 

	 WHERE 

	 data.owner = indx.owner(+) 

	 AND data.owner = lob.owner(+)) 

	 WHERE owner in ('LOCADORA','MEUESQUEMA') 

	 ORDER BY owner;