How to calculate average no of calls per month

[mahnoor1279]

I have data of calls having contact numbers and  details of duration of calls  and i want to know about the average calls per day and per month w.r.t contact no

[brunobertels]

maybe somethink like this 

count (contact) / count (distinct Month) average per month 

count (contact) / count (distinct Date ) average per day 

[mahnoor1279]

This doesn't seems correct !

after using this expression 

=COUNT(CONTACT_NO)/COUNT(distinct(complete_call.MonthYear))