database 1.2G, pg_dump 73M?!

I have a postgres server for which du reports
1188072 /var/lib/postgresql/8.2/main
on Linux system.
The server has only one real database, which is for bacula. When I dump
the database, it's 73Mg.

This is immediately after I did a full vacuum and restarted the server.

Also,
bacula=> SELECT relname, relpages FROM pg_class ORDER BY relpages DESC
limit 15;
relname | relpages
---------------------------------+----------
file_jpfid_idx | 27122
file_pathid_idx | 17969
file_jobid_idx | 17948
file_pkey | 14580
file_fp_idx | 12714
file | 11558
file_filenameid_idx | 9806
filename | 3958
filename_name_idx | 2510
filename_pkey | 1367
path | 966
path_name_idx | 950
path_pkey | 151
pg_attribute_relid_attnam_index | 46
pg_proc | 45

It seems very strange to me that there is such a difference in size
between the dump and the database: the data store is almost 15 time
larger than the dump.

Is this to be expected (e.g., from the indices taking up disk space)?
Is there anything I can do to reclaim some disk space?

Thanks.
Ross