Struggling with cumulative charts

I’d like to create a chart that shows a cumulative growth line, and I’m really struggling to do this.  There were early posts with potential solutions to this problem, but nothing worked.  

Has anyone been able to achieve this?  If so, how?  Open to all ideas.

The dream is to have each column (or point) highlight the value of the current Day/Week/Month, as well all the values that came before it.  (e.g. Jan shows Jan, Feb shows Jan + Feb, March shows Jan + Feb + March, etc…)

I believe those early forum topics described creating additional series on the fly using a before render snippet.  Check this one out.

Now you will need to do the work in javascript to create the cumulative calculations.  But google should be your help here.