If you do not run stats on Oracle database the performance degrades over time.  The statements below will show the last stats update date/time.  You must change the OWNER to match your schema of course.

select min(STATS_UPDATE_TIME) from ALL_TAB_STATS_HISTORY
where OWNER = ‘ADMUSER’

select * from ALL_TAB_STATS_HISTORY
where OWNER = ‘ADMUSER’
order by STATS_UPDATE_TIME ASC