Natstar, the thing is, who's to say that the 2003 year 12 people on here are any different to this years' year 12? I would put money on a lot of 99+ year 11 students hanging around now, just like there were from your year. I'd say this time next year, the results being posted on this forum would be fairly similar (although, this forum is new and its popularity may well spread in the next year). This website generally seems to attract people who are above average. I don't think that your year is any smarter than normal.
You're right in that going to a private or selective school doesnt' automatically guarantee you a decent mark, you still have to work hard and learn the material, but there is definitely an advantage there (resources, teachers, surroundings). I would also say that 99.1 for a dux isn't an amazing UAI. Plus, that's just one person.