I just did a bit of research and this is what I found on Wikipedia. I hasten to add I checked some other sources to validate the numbers...
England and Wales
In England and Wales 390,127 people (almost 0.8%) stated their religion as Jedi on their 2001 Census forms, surpassing Sikhism, Judaism, and Buddhism, and making it the fourth largest reported religion in the countries.
In the 2001 Census 2.6% of the population of Brighton claimed to be Jedi. The percentages of religious affiliations were:
Christian: 70.0%
No religion: 14.7%
Chose not to respond: 7.8%
Muslim: 3.1%
Hindu: 2.1%
Jedi: 0.7%
Or read
http://news.bbc.co.uk/1/hi/uk/1589133.stm
Made me chuckle.