Last insert/update/delete time for a table

Hi all,

I'm in the process of writing a backup script which only dumps those tables which were changed in the last 24 hours. We
have hundreds of tables (one per user), but most of them don't get changed very often, so there's no point in dumping
them every night.

Is there a way to get the time of the last insert, update or delete statement for a specific table?

Regards,
Aleksander