I can only report that among the people who started studying physics with me about 10-15% were women. From the boys up to 30% quit before they got their undergraduate exams (Vordiplom) or final exams and from the girls it was about 10% again. Among the PhD candidates the ratio was between 1:3 and 1:10, some groups having no female candidates by accident. Accelerator maintenance was not that popular in general and so was theoretical hadron physics.
In the math department, the ratio was 1:1 or even 1,5:1.
In the engineering departments, the ratio was below 1:10 but no one cared.
I started studying just one year before the university started to change to Bachelor/Master system (lucky me!); I do not know about current ratios but I don't assume something has changed.