I want to create some kind of portfolio chart for purchasing.
The x-axis shall show the supply risk.
The x-axis shall show the costs.
I only want to differ between high and low for both - risk and costs.
The bubble size will be defined by the purchasing volume of the product
category.

How do I use the text "high risk", "low risk", "high costs" and "low costs"
as description of the axis. At the moment it automatically creates me figures
there.