Identify most scanned tables

Identify the top 20 most scanned tables. 

set linesize 400
set pagesize 3000
col Owner format a15
col Object_Name format a30

select /*+ all_rows */
       *
from
    (select Inst_ID
           ,owner
           ,object_name
           ,value
     from   gv$segment_statistics
     where  statistic_name ='logical  reads'
     and    object_type='TABLE'
     order by 3 desc)
where rownum < 21
/