That would be about 143 a year. Even assuming many leave after their O.W.L.S., we can probably round it up only to about 200. And this is supposed to be the only school for wizards in Great Britain. Even if wizards live to be a hundred, that would make the population about 20,000.
And yet it manages to have an enormous government, with seven floors of the Ministry of Magic. Arthur Weasley has ten people reporting to him in a department about counterfeit devices that claim to afford protection. Who is around to do the work such as farming and manufacturing? They've got to eat. True, we have on-stage shopkeepers and healers. . . but not much more. Nor are the jobs suggested in the career brochures.
Then it occurred to me that the humans might be concentrated in government because they've taken over that aspect. After all goblins control banking and do a manufacturing. There are a good number of Good Folk who did agricultural work. The goblin and giant revolts suggest that the human have expected to control them for a long time. (One wonders how bad that is -- assuming those beings are as nasty as they can be in folklore.)
Which would really explain Remus Lupin's difficulties in employment.
All of which is pure fannish speculation, of course, because there's not enough evidence in the books for it.
