How many movies have Günther Hunold and Wolf C. Hartwig collaborated on?

They have worked on 6 movies together! Their first movie together was Schoolgirl Report Part 1: What Parents Don't Think Is Possible (1970) while their highest rated movie together was Schoolgirl Report Part 5: What All Parents Should Know (1973). They have not worked together since Schoolgirl Report Part 12: If Mom Only Knew... (1978). They are most known for their drama films together.