I am trying to not use any add-ins or BI tools.  I'm wanting to use a pivot 
table to create a histogram (graph) that shows:

A.) Count of new action items for the week
B.) Count of action items resolved for the week
C.) The cumulative count of unresolved action items for the week

My columns are in a table called tblMain and I figured I could get by using 
columns [ID] (a unique ID number) and [DateComplete] (a short date).  
Filtering out the action items that weren't completed is easy enough using a 
"null" qualifier for the date field if it's not yet resolved and using a 
count function works well to get the number of new items added to the 
database for that week (as well as the resolved items).  What is killing me 
is the cumulative count of open action items!  I have no idea where to even 
start on this one.  Any ideas?