Oracle Database Discussions

I have the following queries to find information about rollback segments.

I want the sql to find % of rollback segment used.

*******************************************
--rollsegs.sql
select SEGMENT_NAME, OWNER, TABLESPACE_NAME, SEGMENT_ID, status
from dba_rollback_segs order by segment_name;
--
select name, extents, writes, xacts, gets,waits, shrinks, aveactive, status
from v$rollname n, v$rollstat s
where n.usn = s.usn
order by name;
--
--rolbstat.sql
select name, rssize, hwmsize "High", optsize "Opt", wraps, extends, shrinks,
aveshrink "Aveshr", aveactive "Aveact"
from v$rollname n, v$rollstat s
where n.usn = s.usn
order by name;
set numformat 999999990;