Population of Christians in England dwindle

The number of Christians living in England and Wales has fallen by four million in the past decade, the 2011 Census reveals.
The data shows that numbers fell from 37.3 million in 2001 to 33.2 million last year.
The statistics emerged as the Archbishop of Canterbury claimed that English cathedral congregations had grown dramatically in recent years, debunking the "cliche" that the Church of England is fading away.
Should Christians elsewhere worry about this trend?