Grouping Results Based On Date By Month

I need a subgrouping for a report I am working on.

I have a DateIn field that contains date as mm/dd/yy. I have managed to get a count of all of a certain type of document that came in during a certain period of time that usally spans a quarterly period. So typically there are three months in the query. I would like a subgroup that breaks the numbers up in the 3 month period by each month.

So if a total of 150 docs moved in 3 months it shows 50 moved the first month, 50 the second, etc. I believe this is grouping by month. I have not been able to determine the criteria for getting the query to group by a single month as well as the three months period being grouped by document type. Here is what I have so far.

SELECT ctblDocuments.DocTypeID, tlkpDocTypeList.DocType, Count(ctblDocuments.DateIn) AS CountOfDateIn
FROM ctblDocuments INNER JOIN tlkpDocTypeList ON ctblDocuments.DocTypeID = tlkpDocTypeList.DocTypeID
WHERE (((ctblDocuments.DateIn) Between #7/1/2005# And #9/30/2005#))
GROUP BY ctblDocuments.DocTypeID, tlkpDocTypeList.DocType
ORDER BY tlkpDocTypeList.DocType;