Counting Dates And Null Values In Charts

Hi, I searched the forum for this but the only thread that came close to what I was looking for was this.

http://www.access-programmers.co.uk/forums/showthread.php?t=125240&highlight=null+chart

Basically I have chart in a report thats based on a query that counts the amount of entries per month between two dates inputted by the user.

It all works fine but the chart that is based on the query only shows months that have an entry.

Eg if it counts all dates between the two dates and say the only month that has an entry is July, the chart will only show July. What I want is the other months to show (Null values) as zero, so every month shows. I'm probably missing something basic but can anyone help?

[TextPriDate] is the start date
[TextPriDate2] is the end date

This is the query code (QryDate)
SELECT
tblMain.ID1, tblMain.Dt
FROM
tblMain
WHERE
(((tblMain.Dt) Between [Forms]![frmSwitchboard]![TextPriDate] And [Forms]![frmSwitchboard]![TextPriDate2]));

This the code from the chart in the Report
SELECT
(Format([Dt],"MMM 'YY")) AS Expr1, Count(*) AS [Count]
FROM
QryDate
GROUP BY
(Format([Dt],"MMM 'YY")), (Year([Dt])*12+Month([Dt])-1);

Thanks