Have a look (e.g. using Google Groups) at the conversation titled "Merge
recipient multiple times" started by "Laser Apparel" on 11 Oct 2007.

There is another method that may work for you, as long as you know the
maximum quantity. It needs some Word VBA to set up the data source. It may
not work if there are a large number of labels, or if you have "memo" type
data (long text fields).

Suppose your data is in an Excel file called c:\mydata\labels.xls, is in
Sheet1, and has three columns:

k,labeldata, quantity

k needs to be a unique identifier for the record (because it is used in a
sort). If necessary, you might be able to use labeldata or a unique
combination of the other fields for this value

Create a new Excel file called c:\mydata\multiplier.xls. In Sheet1, create
one column called multiplier and put the following data in it:

1
2
2
3
3
3
4
4
4
4
5
5
5
5
5
...
and so on (i.e. you need 15 rows with the number 15, 100 rows with the
number 100. The largest number must be equal to or greater than the maximum
number in your "quantity" column.

Use the following Word VBA to connect to the data source:

Sub ConnectMultiple()
' You can define more of the constants here if you really want
Dim strData As String
Dim strKeyColumn As String
Dim strQuantityColumn As String
Dim strMultiplier As String
strData = "c:\mydata\labels.xls"
strKeyColumn = "k"
strQuantityColumn = "quantity"
strMultiplier= c:\mydata\multiplier.xls"
ActiveDocument.MailMerge.OpenDataSource _
 Name:=strData, _
 SQLStatement:="SELECT [d].* FROM [" & strData &"].[Sheet1$] [d]" & _
                           " LEFT JOIN [" & strMultiplier & "].[Sheet1$]
[m]" & _
                           " ON [d].[" & strQuantityColumn & "] =
[m].[multiplier]" & _
                           " ORDER BY [d].[" & strKeyColumn & "]"
End Sub

Make sure there is a space after the " in those last few lines.

For further info. on how to install and run Word VBA Macros, see e.g. Graham
Mayor's article at

http://www.gmayor.com/installing_macro.htm

If you do try this please preview the records to check that the correct
number of each record has been inserted. I would also be interested to know
if it works for you.