Wizarding numbers

[mikaelraaterova]

No: HPFGUIDX 82955

[This is my first post here. Please be gentle...]

I've been thinking a bit about the number of wizards, and the posts I 
found when I searched to see what people had already come up with 
weren't satisfying. To calculate the size of the wizarding population 
from the number of students at Hogwarts, we need to know (at least) 
three parametres: the age distribution of wizards, the fraction of 
muggle-born students, and Hogwarts attendance.

- The age distribution among wizards. While they seem to be able to 
live pretty long (Dumbledore is 150, and Mrs. Marchbanks should thus 
be even older), they also seem to live violent or at least risky 
lives. I'll assume that the wizarding world has a pretty high mean 
age comparable to Sweden, for which I have data. Children aged 0-10 
make up 12 % of the pop, ages 11-17 make up 9 % and ages 18+ make up 
the rest. 

- The fraction of muggle-borns (the parents of muggle-born students 
don't add to the wizard population, while their children do). In 
PS/SS, "Harry was very relieved to find out that he wasn't miles 
behind everyone else. Lots of people had come from Muggle families 
and, like him, hadn't had any idea that they were witches and 
wizards" (p. 101, Bloomsbury pbk). So, a pretty big fraction then. 
Let's assume 50 % for simplicity. This seems a bit too high, but OTOH 
that will compensate for the number of halfblood students; they only 
have one parent adding to the wizard pop. 
 
- Hogwarts attendance. GoF says that Hogwarts, Durmstrang and 
Beauxbatons are the *largest* schools in Europe, implying that there 
are small schools as well. So, there may be local schools (and home 
schoolers!) that absorb a fraction of the students within 
Hogwarts' "drainage basin" that would otherwise go to Hogwarts. The 
larger the fraction of non-hogwarts children, the larger the maximum 
population of wizards is. So I assume 50 % to not underestimate the 
pop size. 

So, 500 students at Hogwarts have wizarding parents. Add 500 non-
Hogwarts wizard children not attending Hogwarts. These 1 000 students 
make up 9 % of the wizard pop within Hogwarts "drainage basin" for a 
total of about 10 000 (of which about 2 000 are non-adults; thus 8 
000 adult wizards and witches). To this must be added the 500 muggle-
born students. I'll note that there is also about 500 muggle-born 
children with magical talent that will in time attend Hogwarts, but I 
wouldn't count them to the wizard pop, since they don't know of the 
wizarding world yet.

Another question is 10 500 wizards and wizards-to-be for how many 
muggles? Given the names of known Hogwarts people, I'd say that 
Hogwarts cover the british isles (UK and Ireland) which has a pop of 
64 million people. So, one adult wizard or witch per 8 000 muggles. 

If the proportion of wizards to muggles is the same the world over, 
then the global wizard pop is about 1 million. 

Thoughts and comments?

/ Mikael