Can you create 0 values from no data?

I am creating a graph to analyse curves by a monthly period, and quantity.
The information for this graph comes from a .CSV report that has been exported from accounting software.
In simple terms the CSV looks a little like this...

Month__Qty
1_______2
2_______3
5_______1



As you can see months 3 and 4 are missed out as there was 0 Qty, and thus nothing to report.
When creating a graph using this information, I want the graph to report 3 and 4, as a '0' value.
Is this possible in an excel graph? As entering the 0 values is not an option, as the .CSV report, is to large to enter these manually.

Thanks.