Take a look at the list again and consider who has a national class and then count the type of sailing.... eg.
Single handed
Double handed
Three or more in the boat.

Drum roll ............. For national 2 person classes... the winner is

Double Hander National
11) Hobie 16 54
13) Star 52.7
15) Snipe 50.3
19 Vanguard 15 47.3

WAY TO GO HOBIE 16 CLASS on the three year average..... Beating out the Star Class is impressive!

(I toss the 29ner because it is a junior class in the USA)

The other take home point is to recognize that sail boat racing is indeed social... MANY of the top 25 classes are raced with three or more on the team....