If I do a datamapping with my personal data and I choose to divide a field by another one (in one record this field is 0), the record with the DivideByField value equal to 0 isn' considered.
Let me show you an example
I want to calculate the Total amount of 2003 divided by Total Amount of 2002 per Region (in this case, I suppose I have only one region)
I choose for the datamapping:
field = Amount2003
DivideByField = Amount2002
The result is (100+300)/(2+4) instead of (100+300+500)/(2+4+0)