I hate to spoil the award ceremony ;-), but I'm not convinced that Nausicaa's translation with "Einzelmarkt" is correct. I do find pages like http://en.auto.de/magazin/showArticle/article...
for "Einzelmarkt" (though it doesn't seem to be a very common expression), but I'm not convinced that "single market" is used with that meaning at all. If you google for 'single market', it's all about Binnenmarkt, not Einzelmarkt. (I for one can't come up with an example sentence where I might read "single market" as "Einzelmarkt".)
And then in the original, if it was used as an idiom, it'd be more likely to read "single market for tourism" (to keep the idiom together), not "single tourist market".
So, um, at the risk of sounding stubborn ;-), I stand by "biggest single", translated as "(mit Abstand) größter".