Number of students at Hogwarts

Hi,

I was wondering how many students are technically at Hogwarts. It's kind of a contreversial topic.

~There are about 5 boys and 5 girls in Gryffindor in Harry's year, making 40 students a year. Multiply that by 7 and you end up with 280 students total.

~However during Quidditch matches it's described as to be '200 students supporting Slytherin' and we know Ravenclaw and Hufflepuff were supporting Gryffindor.

~The train is always almost completely full and it's understood to be a giant train.

~The sorting takes time to complete, but not _that_ much time or no time at all.

Therefore, I was wondering how many students could actually be found at Hogwarts. Was Harry's year and the years surrounding it exceptionally small because of the Great Wizarding War? Did Harry _never_ mention the other 20 people in his class?

Curious,

Lily