I've one table with these 3 columns.

LOGDATE ZONE NUMBER
-------------------------------- --------- ---------
"10/24/2005 10:21:15.303000 AM";"SPAFTER";0
"10/24/2005 10:21:16.663000 AM";"SPAFTER";0
"10/24/2005 10:21:16.722000 AM";"SPAFTER";1
"10/24/2005 10:21:16.740000 AM";"SPAFTER";2
"10/24/2005 10:21:16.749000 AM";"SPAFTER";3
"10/24/2005 10:21:17.589000 AM";"SPAFTER";4
"10/24/2005 10:21:17.596000 AM";"SPAFTER";5
"10/24/2005 10:21:18.480000 AM";"SPAFTER";5
"10/24/2005 10:21:19.053000 AM";"SPAFTER";5
......
"10/24/2005 11:27:19.053000 AM";"SPAFTER";51

Need to right one sql which will give me the average of number for 5 minutes duration.