The hottest read in Norway this year is packed with polygamy, prostitutes – even corporal punishment. But this isn't Fifty Shades of Grey; instead, Norwegians have been rushing to pick up copies of the Bible.

Published last October, a new Norwegian translation of the Bible has been one of the top 15 bestsellers in the country for 54 out of the last 56 weeks, jostling for position with more populist titles from the likes of EL James, James Nesbø, Ken Follett and Per Petterson. It is now one of the bestselling books of the year, according to Dag Smemo, project manager for publisher the Norwegian Bible Society, with 157,000 copies sold in the last 14 months, and more time in the charts than both Fifty Shades of Grey and Justin Bieber's autobiography.

Smemo puts the popularity of the book – among Christians and non-believers alike – down to the strength of its translation. The Bible Society worked with Hebrew and Greek experts on the original text, and then involved literary writers including A Death in the Family author Karl Ove Knausgaard to perfect it.

"It's always a very touchy issue, doing a new translation of the Bible," said Smemo. "People say they like it the way it is. But we had a very thorough procedure, involving authors and poets, secular people and believers, and discussing the whole translation word by word, so there is not only a good translation of the Greek and Hebrew but also a very good flow of the Norwegian language. People are saying that it's very good, and we are seeing this from both conservative groups and more secular groups. It's definitely not only Christians buying it. It's atheists too – people are saying the Bible is important for us, for our culture, and for the nation."

Anne Veiteberg, director of the publishing department at the Norwegian Bible Society, agreed. "It has been said that the new translation is closer to modern Norwegian language and therefore easier to read, and at the same time it is closer to the original texts in Greek and Hebrew than older translations when it comes to style and poetry,

images and metaphors. The Bible 2011 is therefore perceived as more poetic as well as a great piece of literature," she said. "People seem to value the Bible's literary qualities and cultural importance more than before. It is still perceived as the holy scripture and word of God by many Norwegians, but a greater number of people value the Bible as classic literature and cultural heritage too. Congregations and individual Christians are still the largest group of people who buy the Bible, but they are not the only ones."

Smemo admitted the sales had taken the Bible Society by surprise – 157,000 copies is a huge number in a country the size of Norway. "We had a discussion in advance, and the editors thought we'd sell at least 25,000. I said 75,000," he said. "We've sold 157,000 … The surprising thing is that it's the Bible. We've been compared to Fifty Shades. We've said at the Bible Society that it's good we don't only have erotic bestsellers in the charts, but moral books too."