Census?

When I was visiting my boyfriend in Ireland last weekend the Central Statistics Office was distributing the forms for the 2006 Census. My BF's family was amazed that I had never heard of it, so after browsing the web for a bit I found out that the Dutch Statistics Office performed a virtual census in 2001 instead of a paper procedure. I wonder how reliable this virtual procedure is, but then again, if half the population inserts Jedi Master as religion the paper version will also not work, so I'm not sure how useful the results of these things are..