last_vacuum field in not updated

Hi,
I am using Postgresql 9.2 where I have a table "table1". I used vacuum
command in that table, but last_vacuum column of pg_stat_user_tables has
not been updated.
Any idea for it?

\d table1
Table "public.table1"
Column | Type | Modifiers
------------------+----------+--------------------
batterysessionid | integer | not null
processedflag | smallint | not null default 0
Indexes:
"table1_pkey" PRIMARY KEY, btree (batterysessionid)

qualitycore=# select * from pg_stat_user_tables where last_vacuum =
'2013-07-28 20:04:34.821115-04';
-[ RECORD 1 ]-----+------------------------------
relid | 5452445
schemaname | public
relname | table1
seq_scan | 55394
seq_tup_read | 458097965
idx_scan | 3056888
idx_tup_fetch | 345092348
n_tup_ins | 1023618
n_tup_upd | 643602
n_tup_del | 642037
n_tup_hot_upd | 175225
n_live_tup | 381549
n_dead_tup | 77130
last_vacuum | 2013-07-28 20:04:34.821115-04
last_autovacuum | 2013-05-01 00:55:01.970799-04
last_analyze | 2013-07-28 20:04:34.903569-04
last_autoanalyze | 2013-05-01 06:04:12.905961-04
vacuum_count | 93
autovacuum_count | 248
analyze_count | 95
autoanalyze_count | 560

qualitycore=# vacuum table1;
VACUUM
qualitycore=# vacuum verbose table1;
INFO: vacuuming "public.table1"
INFO: index "table1_pkey" now contains 381973 row versions in 1878 pages
DETAIL: 0 index row versions were removed.
104 index pages have been deleted, 103 are currently reusable.
CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO: "table1": found 0 removable, 1120 nonremovable row versions in 10
out of 2286 pages
DETAIL: 0 dead row versions cannot be removed yet.
There were 1538 unused item pointers.
0 pages are entirely empty.
CPU 0.00s/0.00u sec elapsed 0.00 sec.
VACUUM

select * from pg_stat_user_tables where last_vacuum = '2013-07-28
20:04:34.821115-04';
-[ RECORD 1 ]-----+------------------------------
relid | 5452445
schemaname | public
relname | table1
seq_scan | 55394
seq_tup_read | 458097965
idx_scan | 3056888
idx_tup_fetch | 345092348
n_tup_ins | 1023618
n_tup_upd | 643602
n_tup_del | 642037
n_tup_hot_upd | 175225
n_live_tup | 381549
n_dead_tup | 77130
last_vacuum | 2013-07-28 20:04:34.821115-04
last_autovacuum | 2013-05-01 00:55:01.970799-04
last_analyze | 2013-07-28 20:04:34.903569-04
last_autoanalyze | 2013-05-01 06:04:12.905961-04
vacuum_count | 93
autovacuum_count | 248
analyze_count | 95
autoanalyze_count | 560

Please let me know.

Thanks.