Scheduled Job Table Problem

Hi Experts,

I have a query regarding the job scheduling in sap . In our plant every day 8500 no of job is running . But in the database table TBTCP or TBTCO we are not getting the jobs older than 10 days . I have searched in transaction ‘SM37’ , but I am not getting the proper data there also .So my question is that why the data older than 10 days is missing in these two tables ? Is there any other able which contains all the scheduled job data older than 1 year?

Thanks and regards ,

Deb