Dynamically changing column headers with calendar years
Dynamically rename column headers with calendar years. This does not take into consideration what the original column headers are. This is specific to the request, and there are some assumptions that are made:
1. There are x2 the amount of columns of the number of years needed (the years + the spend columns)
2. The columns to be renamed are in the order of the years, and the years columns are first, followed by the spend columns