Average Message per hour

Hello experts,

I am trying to calculate Average message per hour.  There were couple of similar post but none worked as per my requirement. Seems to be straight forward but not really. It can be better explained with an example.

I have a datetime table with datetime column and Hour column . Each date will have 24 rows determined by the Hour column starting from 0 to 23 as there are 24 hours in a day. Hour column is a text field as I don't want it to aggregate.  If the date range is selected from 1st May 2019 to 5th may 2019, the total hours (

Avg message per hour = DIVIDE([Count of Post],[total hours],0)

Avg hour = 
VAR HOURCREATION= 
FIRSTNONBLANK(DateTime[Hour],DateTime[Hour])
RETURN
DIVIDE(
CALCULATE(COUNTROWS(Posts),ALLEXCEPT(DateTime,DateTime[Hour])),
COUNTROWS(
SUMMARIZE(
FILTER(ALL(DateTime),DateTime[Hour] = HOURCREATION),
DateTime[Hour])
)
)