Trying to find average between two columns time

[teegarden7070]

index=phantom_container AND owner!=null AND close_time!=null
| eval st=strptime(create_time, "%Y-%m-%dT%H:%M:%S")
| eval et=strptime(close_time, "%Y-%m-%dT%H:%M:%S")
| eval Dur=(et-st)/60
|table create_time close_time Dur id container_label owner_name

Here is the basic search, now I would like to find the average amount of time between create_time and close_time per owner_name. 

[ITWhisperer]

index=phantom_container AND owner!=null AND close_time!=null
| eval st=strptime(create_time, "%Y-%m-%dT%H:%M:%S")
| eval et=strptime(close_time, "%Y-%m-%dT%H:%M:%S")
| eval Dur=(et-st)/60
|table create_time close_time Dur id container_label owner_name
| stats avg(Dur) as average by owner_name

[teegarden7070]

Thank you!