They are saying "the first n car shows"
Now this could be interpreted in two ways.
1) The first n "annual" car shows. This is what you are saying I believe, then it makes perfect sense.
2) But they could also be talking about individual car shows. For example in the first annual car show (2004), there were 38 car shows and n of them (where n < 10) had the specified pre-registration and on-site registration fees. This is how I interpreted it. In the sense there every car has an individual "show". But I get your point that all cars combined is what they mean by "car show" over here.
Regardless, not super pepped about the wording here. They should have used the word annual.
Bunuel
You’re wrong. We are in fact given clear data about the registration fees: for the first n years, they were $10 and $12, and for the remaining years, both fees were higher. Since 2005’s numbers fit perfectly with $10 and $12, that means 2005 was one of those early n years.
But 2006’s data doesn’t fit those same fees. With 28 preregistered and 67 on-site, 10 and 12 would give only $1084 (28*10 + 67*12 = $1084), not $1341. So 2006 must have been the first year when the registration fees rose.
You can even see this without doing the math: the total number of cars changed slightly, from 92 to 95, yet the total revenue jumped from 1040 to 1341. Three extra cars could not have produced $301 more in revenue under the same fees. Hence, both preregistration and on-site fees must have been higher in 2006.