Last Created/Updated Table ??

How I can know when a table was last created or updated (structure change, or constraints change). I queried pg_class, pg_tables but it does not have any 'date' type field.

The requirement is as follows...

1. Identify table(s) that have been created/modified recently.

2. Identify the change in foreign key constraints for that table, if any.

3. Update scripts to reflect changes in table structure and constraints.

I can do 2 & 3, but 1 is bugging me !

Any pointers ?

Thanks & Regards.