"The Cardiff University study, published online today in the journal Sociology, says that the proportion of adult Muslims actively practising the faith they were brought up in as children was 77%. That compares with 29% of Christians and 65% of other religions.Talk about "good and bad news"! The downside of such a study is that many people who identify as Christians, but don't give a toss about religion in their daily life, will suddenly feel the urge to compete with the muslims. Instead of embracing our secular future, they may turn around and cling to the past only because the Muslims do it.
The study also found that 98% of Muslim children surveyed said they had the religion their parents were brought up in, compared with 62% of Christians and 89% of other religions.
The team analysed data from the Home Office’s 2003 Citizenship Survey data, using 13,988 replies from adults and 1,278 from young people aged 11 to 15.
Home Office statistics show that 74% of people in Wales are Christians but that only 7% of those attend church."
Walesonline.co.uk, Feb 13 2012 (Found via Islam in Europe)
On the other hand, 27% apostates within Islam is not a bad number considering how Islam is portrayed.