How many kids are at Hogwarts??

[karenweise at hotmail.com]

No: HPFGUIDX 11956

I apologize ifthis has been discussed already, I'm rather new here.  
I've been thinking about how many students there are.  There are only 
5 boys and 3 girls in Harry's year.  Even assuming this is a smallish 
number (and normal should be 10 of each sex per year) or that JKR 
somehow hasn't mentioned the other boys and girls in Harry's year, 
that still only leaves you with 560 kids.  Am I missing something? 
Most schools for this range of ages are a lot bigger.  Help!

Karen