Mini 2007 Power Steering Fluid Level
 

I have a 2007 Mini and while checking fluid levels, I noticed the power steering reservoir appears to be low. On the cap of the reservoir, there is a "measuring" stick with no marks on it, but has 3 steps on it. I know the fluid that must be added is CHF 11S. How high or full must the reservoir be?

Thank you for all responses.