"WE'RE more popular than Jesus now," John Lennon boasted of The Beatles in 1966. Another shaggy superstar-Father Christmas-can make a similar claim. Based on the number of times "Santa" and "Jesus Christ" have been mentioned in English-language books or journals, Mr Claus surpassed Jesus around the start of 20th century. Secularists seem to have the wind at their back in other respects, too. Book references to "Christmas" have steadily risen over the past 200 years; mentions of "Christianity" itself have fallen, closing the gap between the festivities and the religion that lies behind them. The accoutrements of the modern Christmas, from the Christmas tree to the Advent calendar, have appeared more frequently in books and journals in recent decades (see chart below). Although the calendar has spiritual origins, its real purpose now is to celebrate popular graphics.
http://www.economist.com/blogs/graphicdetail/2014/12/daily-chart-6