I'm a history grad student, working with a bunch of arms trade data.
In my database, I have IDs associated with multiple countries. In the year 1862, for instance, one record states "England, Scotland and Ireland", and so this ID is associated with three different countries: England, Scotland and Ireland. When I sum up all the activity in 1862, it treats these three countries as different instances, triple counting the data. In 1862, for instance, there should be $1615 of gunpowder exported from the US; the calculation I have triple counts the amount for "England, Scotland and Ireland" ($15) making the total $1645.
I've attached the packaged workbook.
I assume that I have to make a calculated field, but I'm not sure exactly what to do to ONLY count one of these values?