Autovacuum daemon internal handling

Hi,

Our production server is running PostgreSQL v8.2.3 on Red Hat Enterprise
Linux Server release 5 (Tikanga).

I need a clarification on how autovacuum daemon internally works/handles in
the following specific use case/situation:

1. Does autovacuum daemon works with one table at a time or does it work
with multiple tables at the same time?
Reason to ask this question is, let's say I've "autovacuum_naptime" set to 1
minute, and there are 500 tables in one database. Assuming there are 10
tables that has to be vacuumed and analyzed based on the threshold defined
in one of the autovacuum daemon execution time, and if takes more than 1
minute to complete vacuum and analyze operation on even a single table (out
of 10 tables), how does autovacuum daemon works/handles in this case?

2. The columns "last_autovaccum" and 'last_autoanalyze" in
pg_stat_user_tables shows the start time or end time of the operation?

Regards,
Gnanam