how to get success, deferral, failed statistics?

Hi,
i really can't understand how to get statistics, in numbers, about how
many sent mail got success, or deferral or failed up to -the moment i need
them-.

Of course ezmlm knows if a subscriber of an email got a "success" or
"deferred" or "failed" from qmail-send, otherwise it can't choose who to
send to!

So i was wondering how can i get this information, a command, a tool, or
files where i can get infos per subject, per mailing list, and infos on
the subscriber (cause i want to discover also if there is some address
that does not exist anymore, and other details...)

Thanks in advance

--
mr