How to create a chart for past 12 months

Question

Our objective is to show month by month the cumulative growth of new accounts for the past 12 months.
I know how to do cumulative. The problem is that for some of the months, we don't have new accounts. My pivot table only has those months that have new accounts. E.g. Month 1, Month 4, Month 5, Month 7, Month 10, Month 12. What I want is to have those months that do not have new accounts to have the same cumulative total as the prior month. So in my example, if Month 1 Cum = 10, then Month 2 Cum = 10, Month 3 Cum = 10, because Month 2, Month 3 do not have new accounts. This way, the chart would show data for each month.
How do I do that?

Answer 1

My requirement was slightly different, I had to built a report showing how many opportunities are going to a particular stage / week end (1/2/2009..1/9/2009 etc). I noticed that we do not have opportunities that goes to a particular stage in a certain week but still my chart should show there is a goal of 10 opportunities for that week end.
What i did was i created 52 activities with a certain type (visible only to me) with a completed date of the specific weekend (It's a pain to create 52 activities, so i mass imported them). Now having done that i created a union of sales stage report and activities report. In both sales stage and activities i put filters to show case only the information that i need to see. Once i did this then i built pivots of the same.
In your case i would suggest you create 12 activities one for each month i.e completed date 1/1/2009, 2/1/2009 etc. Then you build a accounts report with your specific conditions that would pertain its a new account. Let's say you have two fields # of Accounts, Month of created Date
Unionize with Activities (filter for getting only the 12 activities that you created). Put two fields # of Activities, Month of Completed Date. Change the formula for # of Activities to 0 and rename the field to say # of Accounts.
Once you do this build a pivot table and you will get your report. You can chart it if you want.