I have a data set that each line of data represents the totals for the previous week. I would like a chart that shows the previous 6 months of data (ie 26 lines of data), and updates automatically when a new line of data is added each week.

I have read the following on dynamic charts:

http://www.techrepublic.com/blog/mic...arts-in-excel/

But this just explains how the chart will pick up new data, I want to know how we can limit this to 26 lines of data only.

Thanks for any help.