Some UK statistics:
That is true, but not really to do with the point I was making.
Disbelief/denial leads to a different lifestyle than a practicing Christian.
Only 30% of UK prisoners profess no religion
32% of prisoners in England and Wales on 30 June 2010 professed no religion, the identical figure to March 2000, although the prison population had increased by 30% during the course of the decade.
24% of prisoners in 2010 claimed to be Anglicans, 17% Roman Catholics, 7% other Christians, 12% Muslims, and 5% of other faiths.
The percentage of Muslim prisoners has almost doubled since 2000, partly reflecting the natural growth of Muslims in society at large, and partly the concentration of criminals among young and economically disadvantaged people, who are disproportionately Muslim. 59% of Muslim prisoners were aged 15-29 compared with 47% of all prisoners.
Roman Catholics were likewise over-represented among the prison population, relative to the community as a whole, albeit their proportion of prisoners has not changed since 2000. This is a long-standing phenomenon and has recently been subject to detailed investigation in Scotland.
60% of Scottish Prison Population are Religious
As at 30 June 2013 just over 4,600 prisoners (58% of the prison population) in Scotland indicated that they held religious beliefs. Of these, 93% were Christian (of various denominations). Muslim prisoners accounted for 4.4%. Together Buddhist, Sikh, Jewish, Hindu and other religions accounted for 2.7% of the religious prison population. Just over 3,270 prisoners (42% of the prison population) held no religious beliefs.
The proportion of Muslims among the prison population was greater than that amongst the general population. According to the 2011 Census29, Muslims accounted for around 1.2% of the Scottish population aged 15 and over. In prison the proportion was over twice that at 2.5%.
Aside from the “other” grouping, no other religion had a higher proportion of representation in prisons than among the general population. Individuals with no religious identity accounted for around 41% of the general population and just over 41% of the prison population.
27% of Prisoners in London Jails are Muslims
(I couldn't find more recent UK statistics at short notice
A Pew study found that the majority of US inmates are Protestant Christians
Atheists make up only 0.1 of US Prison Population
There were 139,002 people in the U.S. federal prison system last year, and exactly 143 of them identified as atheists. Those self-described atheists made up a mere 0.1% of the federal prison population.