Reports question: How to generate a total net profit line chart report?

[olimination]

Hi everybody,

I would like to generate a report which shows me my monthly Total Net 
Profit (or loss) accumulated from the month before etc. The 
"Income/Expense Chart" chart just offers me a "month view" but does not 
cumulate the Net Profit from the last month to the next month. The idea 
is to see the trend of my Total Net Profit during a time period.

Thank you for your help,
Oli