Can you share a sample data set in this case...one of the experts around can suggest the format..
Ideally - I would create a table with headers like branch, month, year(can be extracted out of month)..targets..if there are serveral metrics and then achievement..
or Targets can be managed separately as they likely to be fixed for all the metrics..
Rahul - There are several ways of managing this data, however, I am little curious to know your end result...like what do you want to achieve...what should this data finally talk about...
Basis the required final output, It would be easly to suggest the format that is to be maintained..