Numbers from the 2011 census in the United Kingdom show that a majority, 59%, identify as Christian and 25% claim no religion.
Just 10 years ago, 73% said they were Christian and only 14% reported having no religion.
From the BBC :
A spokesman for the Catholic Bishops' Conference of England and Wales said: "The overall decrease in the number of self-identifying Christians is consistent with recent social attitude and social value surveys.
"While this is a challenge, the fact that six out of 10 people in England and Wales self-identify as Christians is not discouraging. Christianity is no longer a religion of culture but a religion of decision and commitment. People are making a positive choice in self-identifying as Christians."
Robert Pigott, religion correspondent for the BBC, notes  that the census allowed just enough space for a word or two about religious identity, and did delve into faith, belief, or practice:
By asking people to state their religion, or lack of it, the census was asking a complex question. But it allows only a one- or two-word answer, obscuring almost as much as it reveals about what has happened to religion during the past decade. Religion is about more than belief. It can be a badge of identity, an inheritance of upbringing or a statement of moral intent.
Rowan Williams, the outgoing Archbishop of Canterbury, remained upbeat and suggested that the Church of England will adapt and flourish. He lamented over the recent defeat of attempts to allow women bishops, but remained hopeful, writing :
“This is not the familiar story of a Church that’s fading away," he writes.
"It should make us think twice before signing up to that particular cliché.”
Referring to his own personal sadness at the defeat of moves to introduce women bishops, he tells how he sought solace in the silence of Canterbury.
“When the Church itself looks dysfunctional or muddled (yes, I have noticed), there are still things that don’t change,” he writes.
“A couple of days after the Church of England’s painful vote on women bishops, I was back in Canterbury, looking at the building and thinking, ‘Not even these past few days take away the open space, the possibilities’.
“The Cathedral still stands; Jesus really was born into this world, a flesh-and-blood fact that never goes away.”
These numbers are released at a time  when the UK considers legalizing same-sex marriage in a way that would prevent the Church of England from compulsion to perform those ceremonies.
Some data-crunchers predict  that self-identifying Christians could be a minority in the UK as early at 2018.