Access 2007 Create a report with totals

I am trying to build a report that will calculate a number of things.  For example, it will give the total number of printers in the database by looping through the SN field.  I would also like it to display the total number by model.  

I am not sure of the best way to do this.  I have a form with a command button that I am trying to pass the value to the report. I understand how to do the loop but I am not sure how to get it to the report.  I am also not sure that this is the best way to achieve my goals.

I would like a report that shows something like this
Total number of Printers = x
Total number of Model1 = x
Total number of Model2 = x
etc.

These values aren't stored in the database and I have to calculate it.  I can get the values with the loop but I don't know how to get those values to the report.  That is what is throwing me a curve ball.

The strArg is obviously not correct in my code.  I made a text box named rptPrintertotal on the report so my theory was to assign rptPrintertotal=x (x being the number of records from loop)

I could be way off base here so let me know.  Thanks!

Dim strArg, x As String
Dim db As Database
Dim rs As Recordset
x = 1
Set db = CurrentDb()
Set rs = db.OpenRecordset("TA")
Do While Not rs.EOF
    If rs![SN] > "" Then
        x = x + 1
    End If
rs.MoveNext
Loop
strArg = "[rptPrinterTotal =] & x" + ";"
MsgBox (strArg)
DoCmd.OpenReport "PrinterTotals", acViewPreview, , , acWindowNormal, strArg

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