How to get values in % w.r.t total of overall column excluding dimension value in Pivot table

[Iras]

Dear all, 

I am facing an issues to get the % values w.r.t total values . below is the scenerio what I am looking for 

The Pivot table in actual :

Groups	05_2016	06_2016	07_2016	08_2016
groceries	4	4	8	5
Electric	5	3	3	4
mail	6	5	2	3
Total	15	12	13	12

I want to convert the above table in % as below

Groups	05_2016	06_2016	07_2016	08_2016
groceries	27%	33%	62%	42%
Electric	33%	25%	23%	33%
mail	40%	42%	15%	25%

To get the values in % I divided count based on Group divided by total count for that particular reporting month. for example: fo Groceries (4) for reporting month 05_2016 i.e. 4/15  i.e. 27%. 

Regards 

Iras

[OmarBenSalem · Accepted solution]

Sum(Sales)/sum(total <Date> Sales)