I found some of this in the book “A Theological Miscellany” by T.J. McTavish. This book is a fun and interesting collection of “essentially inessential facts” about Christianity.
What is the “world’s only officially Christian nation”? That would be Zambia. In December 1991, the president of Zambia declared the nation a Christian state.
By percentage, what is the world’s most Christian nation? That would be Mexico! 99% of the population would be considered nominal Christians. Number 2? France at 98%. The United States falls in at number 7 at 85%. That puts the US behind Brazil, the Philippines, Italy, and the United Kingdom (in addition to Mexico and France). Close behind the US would be Germany at 83%.
Here’s an interesting quote from Greg Boyd’s book “Myth of a Christian Nation.”:
Conservative religious people involved in kingdom-of-the-world thinking often believe that their enemies are the liberals, the gay activists, the ACLU, the pro-choice advocates, the evolutionists, and so on. On the opposite side, liberal religious people often think that their enemies are the fundamentalists, the gay bashers, the Christian Coalition, the antiabortionists, and so on. Demonizing one’s enemies is part of the tit-for-tat game of Babylon, for only by doing so can we justify our animosity, if not violence, toward them… If we were thinking along the lines of the kingdom of God, however, we would realize that none of the people mentioned in the above lists are people whom kingdom-of-God citizens are called to fight against. They are, rather, people whom kingdom-of-God citizens are called to fight for. (pg 48).