I want to know the answer to the following question:
During which financial year did the Melbourne rail network record its highest volume of passenger trips?
All the background I'm provided with is that "The Melbourne rail network has its origins in privately built lines from the 1850s gold rush era, and today the suburban network consists of 209 suburban stations on 16 lines which radiate from the City Loop, a partially underground metro section of the network beneath the Central Business District (Hoddle Grid).". Is that enough to answer the question?