nope.. 500,000 is in total ... most Thai ( around 360 ,000 ) come via border gate.
Source? Most of your tourists come through road and mainly from Thailand. The figure you are quoting is for only those who travel through air.
lol.. do u see Thais , Japanese and Koreans in outside world...? that's easy..
Ok Thais could be differentiated from Japanese and Koreans but how do u differentiate between a Japanese and a Korean? That would be tough.
Here in Chittagong, I can see lots of Chinese, Japanese and some Koreans, Filipinos, Vietnamese. I sometimes find it difficult to differentiate between them. In fact I never knew there are Vietnamese and Filipinos living here until I met some.