Dynamic file.......how to adjust formula to accomodate dynamic file

[welchs101]

I have a file of dates. I import this data into my file once a month. So one month i may have 1000 rows of dates the next I may have 25 rows of dates.

Regardless of the # of rows i have this formula on the 2nd sheet which I would like for it to update automatically if possible.

(see enclosed file)

Things to keep in mind:
Note: Data on "Raw Data sheet " will change. The amount of rows will change. One month maybe more than 182 other months may be less.

Note: Column name shown in col-A will stay the same but may not ALWAYS BE IN COL A. It could be in col K.