More than one per country is fine, but try to keep 'em short. Like so:
Japan: Going for the cultural victory conditions since 1946.
Sweden: Basically Tumblr in physical form.
Greece: Hermes would be crying like a bitch right about now.
Canada: Shitty telecoms, cold as fuck, but great for hermits and oil barons alike!
Mexico: Played the long game to reclaim California by assimilation.
South Korea: You'll never beat a pro gamer from here.