How much time does my stats job ran?

Here is the small script

column job_name format a20
column status format a12
column actual_start_date format a36
column run_duration format a14

select
        job_name, status, actual_start_date, run_duration
from
        dba_scheduler_job_run_details
where
        job_name = 'GATHER_STATS_JOB'
order by
        actual_start_date
;

JOB_NAME             STATUS       ACTUAL_START_DATE                RUN_DURATION
-------------------- ------------ -------------------------------- --------------
GATHER_STATS_JOB     SUCCEEDED    21-JAN-10 22.00.03.629836 +00:00 +000 02:26:12
GATHER_STATS_JOB     SUCCEEDED    22-JAN-10 22.00.05.236441 +00:00 +000 02:37:48
GATHER_STATS_JOB     SUCCEEDED    23-JAN-10 06.00.11.181440 +00:00 +000 01:23:25
GATHER_STATS_JOB     SUCCEEDED    25-JAN-10 22.00.02.629410 +00:00 +000 05:06:38
GATHER_STATS_JOB     SUCCEEDED    26-JAN-10 22.00.01.182149 +00:00 +000 00:11:09
GATHER_STATS_JOB     SUCCEEDED    27-JAN-10 22.00.04.178122 +00:00 +000 00:09:54
GATHER_STATS_JOB     SUCCEEDED    28-JAN-10 22.00.01.500210 +00:00 +000 03:15:44

From the dba_opt_stat_operations,

set lines 100
col operation form a40 wrap head 'operation(on)'
col target form a1
spool show_auto_stat_runs.lst
select operation||decode(target,null,null,'-'||target) operation
      ,to_char(start_time,'YYMMDD HH24:MI:SS.FF4') start_time
      ,to_char(  end_time,'YYMMDD HH24:MI:SS.FF4') end_time
from dba_optstat_operations
order by start_time desc
/
clear colu
spool off

operation(on)                            START_TIME                END_TIME
----------------------------------- -------------------- --------------------
gather_database_stats(auto)         090518 06:09:43.3429 090520 00:00:52.7399
gather_database_stats(auto)         090517 22:00:01.0653 090518 06:01:02.1637
gather_database_stats(auto)         090516 22:00:00.5150 090517 06:00:39.3076
gather_database_stats(auto)         090515 22:00:00.4157 090516 06:01:10.6544
gather_database_stats(auto)         090514 22:00:01.6624 090515 06:01:10.3767
gather_database_stats(auto)         090513 22:00:01.0706 090514 06:01:07.7145
gather_database_stats(auto)         090511 06:01:44.2381 090513 00:01:23.3091
gather_database_stats(auto)         090510 22:00:00.3218 090511 06:00:53.7735
gather_database_stats(auto)         090509 22:00:02.4334 090510 06:01:11.2443
gather_database_stats(auto)         090508 22:00:03.2080 090509 06:01:22.6858
gather_database_stats(auto)         090507 22:00:01.4859 090508 06:01:19.1966
gather_database_stats(auto)         090506 22:00:02.1927 090507 06:03:55.9747
gather_database_stats(auto)         090504 06:00:47.3064 090506 00:00:29.0017
gather_database_stats(auto)         090503 22:00:01.0015 090504 06:00:45.7018
gather_database_stats(auto)         090502 22:00:00.9199 090503 06:00:47.9868
gather_database_stats(auto)         090501 22:00:02.3382 090502 06:01:24.6070
gather_database_stats(auto)         090530 22:00:01.4914 090501 06:01:31.4369
gather_database_stats(auto)         090529 22:00:01.1076 090530 06:01:14.7856
gather_database_stats(auto)         090527 06:01:01.0286 090529 00:01:16.2678
gather_database_stats(auto)         090526 22:00:00.3628 090527 06:00:52.0203