"Latvia: probably helped by the fact that 1/3 of the population lives in the capital city."
And also, before fibre what was the state of their DSL rollout, and after that what was the state of their FTTC rollout? Without those details it's hard to get a genuine idea of how why change has happened. If country A has only had 1MB DSL, and you suddenly make FTTP available then I imagine you'll get a massive take up... but if like the UK you've had decent DSL speeds available (more than enough speed for many users), followed by FTTC for more money, how many people would be bothered about FTTP? You'll only attract those who's needs aren't being met by what they have already. Unless you NEED those speeds is it worth the money? Even as a geek I was fine with DSL, the only reason I upgraded to FTTC was because I got a 4K TV and finally had a need for the extra speed.