I was looking at FC Vaduz out of curiousity and found that their stadium is larger than the population of the town that they are based, (~8k stadium ~5k town) although it doesn't have attendance statistics which will be quite low. So while eating my porridge I had a bit of a google to see what was the biggest attendance as a percentage of population that I could find.
The best i've come up with is Guingamp in Ligue 1, town of 7,500 stadium holds more than 18k, average home attendance of 15k or 200% of the population.
Makes us look pretty apathetic, any bigger examples out there?