I'm trying to get my chart to autmatically update without having to maunually select the data series each month. I am doing this for about 50 sales reps and they each have their own chart. I've tried doing a dynamic range but couldn't figure out if you can do multiple columns? I also tried to make the range an absolute value thinking I could just delete a column and it would still pick up 12 months of activity for the range I specifically selected.

My data is in the format as follows:

Oct10 Nov10 Dec10 ...............................
Steve 55.2 45.8 52.3 .......................
John 25.2 41.5 64.1 .................
Etc.................

I am looking for a 12 month trend.

Any help would be appreciated. I can rearrange my data if necessary.