Grouping records by their respective month and year based on a date column can be done really easily by simply running the following SQL query:
DATEPART(MONTH, DownloadDate) AS Month,
DATEPART(YEAR, DownloadDate) AS Year,
COUNT(DownloadID) AS NumberOfItems
DATEPART(YEAR, DownloadDate), DATEPART(MONTH, DownloadDate)
Year DESC, NumberOfItems DESC
As you can see from the query (above), I am using the "DownloadDate" column to group my records and to also get a count of how many records belong to that month and year.