Gallup (h/t http://thewoundedbird.blogspot.com/). After considerable statistical analysis (cor - look at those low numbers on the West and North East coasts) I have come to the conclusion that Christians are averse to the sea - at least on East and West coasts - so with England being such a narrow country in that respect it is perhaps no surprise that churchgoing is so low here!
Just compare - 15% of the English got to church monthly - 22% in London (pages 5 & 6 http://www.tearfund.org/webdocs/Website/News/Final%20churchgoing%20report.pdf) whereas in America Vermont, with fewest (mostly) weekly attendees has 23%.
[We are ignoring the fact that only 5% of French people are estimated to attend church on the grounds that it doesn't fit our thesis! Much as ACNA supporters claimed General Synod support which was not in fact there http://anglicanfuture.blogspot.com/2010/02/general-synod-member-brian-lewis-on.html]