Mobilized when and for how long?
Doing it for a few weeks is one thing, doing it for months on end . . .
Also, your initial figure (375,000 males) - is that all males or adult males?
I have the number from Bury&Meiggs "History of Ancient Greece to 323 BC" in a footnote(almost a page long in the back) but I don't think it gives further analysis.The 67% is given by Erick Mauraise in his"Introduction of Military History" probably the number reflects the period of a single campaigning season (like the Plateans in Marathon,'all the able bodied men' 1000 in all-but there the precentage was 67& or more).
The Peloponnesian War,as it has been assessed the greatest war in antiquity,offers some very interesting statistics and an insight in the Athenian empire's economics of war.The fact that Athens started the war with 9500 talents(which is by analogy greater than the British empire's 1914 war effort-expenses 186 million pounds a day) of gold in its treasury and the disbursements for the Athenian guard contingents for the 178 cities-subjects of the empire(totalling 20000000 people)-will show the real level of mobilisation.
The rowers of the ships were in their majority Athenian citizens-Thetes-producers of less than 200 bushels of a particular produce per year,that is to say proletarians or there abouts,could not be included in the body of the phalanx-being unable to supply their own arms-eligable to serve in the fleet though as rowers and on landings as light infantry.Further rowers needed were taken from the same class of citizens of allied cities.