Squibs

[jferer]

No: HPFGUIDX 42115

Catlady:"5060 students (K thru 6 = 7 years, some as Hogwarts?) / 
60,000 population ::: 1000 students = 12,000-odd population. Wizarding 
folk live twice as long as Muggles ::: 24,000 population. Larger than 
the 20,000 I estimated, based on how many people are needed to have 
all those shops and businesses."

That's right, K-6.  If you had a much longer-lived population, how 
does the total population change? It won't necessarily double, as 
there's more time for accidental death, etc., among the adults, and 
reproduction rates could be different. So it easily could be your 
20,000 instead of 24,000, and the numbers aren't very far apart 
anyway.  A 20-24K population is still a small society, but you can 
start believing in wizard business, industry, and government at that 
level. Can't do it at, say, a population of 4,000.

Is it possible, although there's no evidence for it, that lifespans 
vary more widely in the wizard world, depending on how much magic you 
have in you? We have to assume wizards are the same as us in terms 
of our bodies. If that is true, Filch can't expect to live a lot 
longer than we can, while Dumbledore can keep going and going...at 
least with respect to natural causes.