I have an XY chart with 30 points (each a single serie, so that I can name
the point). I would like to have a colored quadrant background to group the
points (like a BCG matrix). The lines of the background must be the average
of the points for each axes. The problem is that this normally requires the
axes to start at zero. My points, however, are usually between 80% and 100% -
but not allways.
I did not find a way the make the axes start at a value I define depending
(dynamically) on the data points.

Anybody got an idea, maybe a page?
Peltier has no solution to that.