New figures from the 2011 Census show that the number of people who identify as Christians in England and Wales has fallen by 4 million over the last 10 years -- from 37.3 million in 2001 to 33 million last year, the Religion News Service reports. Meanwhile, the number of people declaring themselves to be atheists rose by more than 6 million, to 14.1 million. "It should serve as a warning to the churches that their increasingly conservative attitudes are not playing well with the public at large," said Terry Sanderson, president of the National Secular Society. Other polls have detected similar shifts: The 2012 British Social Attitudes Survey showed that only about half of Britons claim a religious affiliation, down sharply from 20 years ago when two out of three did. Barely a quarter of young people identify themselves as religious. The new figures also show that Islam is the U.K.'s second-largest religion, at 2.7 million. Hinduism is third, at 817,000, and the number of self-identified Jews rose from 260,000 to 263,000.