Compressed Backup too big

"PostgreSQL 8.2.3 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC) 3.4.2
(mingw-special)"
Database size in disk returned by  pg_database_size() is 210 MB

Database compressesed  backup file size is now 125 MB.
This seems too much. I expect compression to decrease size 10 times, also
indexes are not backed up. A year ago compressed backup size was 9 MB only.

I created query returning biggest tables with and without indexes and found:

      1  pg_toast_22185                      95 MB           96 MB
      2  rid                                 21 MB           27 MB
      3  klient                              13 MB           19 MB
      4  mailbox                             10 MB           11 MB
      5  dok                                 7640 kB         12 MB
      6  desktop                             8080 kB         8200 kB
      7  strings                             5536 kB         6584 kB
      8  pg_toast_22338                      5232 kB         5368 kB

...

Questions:

1. Tables are relatively small and thus cannot create 125 MB compressed
backup file.
Why backup file sis so big ?

2. How to determine what data is containing in  pg_toast_22185  ?
Why this is so big ?

Andrus.