80s Trivia: Which of these nations gained formal independence in the 1980s?

Ahh, the 80s, filled with fun times in banana republics and bigger countries invading much smaller ones.  Yes, you couldn't throw a cat in the 80s without hitting some smaller nation that was in the midst of political issues.  However, there were some political transformations that occurred without any violence or bloodshed.  This is a random one, off our our Pocket Trivia: 80s Trivia:  80s Trivia:  Which of these nations gained formal independence in the 1980s? Was it Mexico, Canada, the USSR or Serbia?

Answer after the jump:

So, here's the rundown.  It wasn't the USSR - they didn't need to be independent from - uhh, anyone.  They were the USSR.  They didn't really break up until 1881 anyway.  It wasn't Serbia - they have spent most of their existance in some sort of state of political upheaval - but they did not gain any independence during in the 1980s, though 1989 did see Slobodan Milosevic rise to power.

That leaves Canada and Mexico, and Canada, with their continued relationship with Britain, would seem to be an obvious answer.  Well, for once, that's the case.  Although Canada was basically independent in 1931, the formal declaration of independence came in 1982.