Well thanks for the reply. I was thinking to devote this forum to gather data on how many years (on average) one needs to stay in one class.

Even though it depends on one's capability to fly well etc, it is my observation that there are few people competing in the two lower classes than in the upper classes. This is true for the number of competitions I went in 2010 and 2011. On the other hand, I remember seeing the same group of people in the upper classes for a couple of years.

Maybe the following is true?

sportsman: 1 year
immediate: 1-2 years
advanced: 3-5 years
Master: 4-<n> years