If any country will ever fully adopt bitcoin it will probably be a very small country. I think a country would probably rather experiment with their own form of digital currency than bitcoin, but I'm not sure if bitcoin would be a safe experiment to use with current volataility.
i think it's already happening. iceland has their own cryptocurrency: auroracoin.
http://motherboard.vice.com/blog/in-one-month-everyone-in-iceland-will-own-cryptocurrencyIceland got the auroacoin via an airdrop that horribly failed. After the airdrop the price fell like a rock. This kind of rollout is almost certain to fail as anyone that gets something for nothing like this will have a big incentive to sell it for fiat instead of use it as a currency.