Task "realWork" history

Hello,

for some reports and help on decision I would like to create a report that is giving all the changes on the "realWork" information of some activities (generally some summary activities).
The scope is to have a graph like the as attached 



I though to use the API to retreive this information (as I didn't find a direct report for it)

I can find the current value of the realWork on the "Activity" element, but I do not know how to retreive all the changes on the History elements, even if I can see them on the History tab of the tool.

Is anybody has some hints to retrieve this information?

Thank you,

Hello Babynus,

I'm coming back on this old subject - I had unfortunately no time to dig into again before^.

Going directly on trhe DB could be an idea, but I do not know how externally I can do that.
So I do suppose I have to create some custom reports (sql+ php), but I didn't find any howto/tutorial or example for creating custom reports.

The other issue, is to have the report exported somehow automatically for a set of projects, to be included into a presentation for steering committees.

Do you have a point where I could start looking for it?