Determine Transactions Per Second

Hello

    I am needing to determine the tps for a production application
running on PostgreSQL 7.4.7. I know you can use pg_bench and create a
new database to determine an estimate of tps. Is there a way I can get
this info out of my production database.

Thanks

--
"What I've done, of course, is total garbage."
        -- R. Willard, Pure Math 430a