Here is my breakdown of this all....
Most of the world doesn't wakeboard. I'm sure there is a person or two in most countries that do wakeboard but honestly most of Asia (LOTS OF PEOPLE), Mid-East ( not Doha/Dubai), most of South America, and.... lets face it, most of the rest of the world doesn't care about wakeboarding. So not a ton of sales will go there.
Cali is huge... only 35 countries have more people than Cali.... Canada, North Korea, Australia, Chili, etc etc etc all have less people than just the state of Cali. That is a lot of consumers, epecially since they are consumers of America (one of/thee most spoiled country around) so things like wakeboards can be purchased.....
I'm sure there are tons of online shops/stores/warehouses that ship based from Cali seeing is that it is on the coast, so all the sales from these online vendors that get boards shipped to everywhere in the world all counts for Cali too.
20% is no shock to me at all.