There's two minor points as hints:
1) Sweden, Norway and Denmark are actually just one case, not three separate ones. [So in these three countries there's just one case of blue while the USA by itself for example has one case of blue, one case of red and one case of yellow]
2) I merged Hong Kong and China, Hong Kong would be yellow and main China would be purple.
@NiRv4n4 No, the positions do not have any meanings. It's really just Red, Blue and Yellow, and when both or all three are present, then the other colours are created. I could've also striped them, but I thought this way was funnier and more headscratching for the first viewing
)
@jtb1127 Isn't everything History? But no, it's not political history, it's a rather contemporary thing, and it's changing.
@Southern King How Exports? I can't see how that would fit with the scale, so no
@Akka Yes, you're right. Plus France may be another special case, together with the Netherlands, but I'm not quite sure how to classify that. (that's another hint...)