(indeed, most people would find it easier to list the religious people they know, as the non-believer category is overwhelmingly the largest)
Between 2001 and 2011 there has been a decrease in people who identify as Christian (from 71.7 per cent to 59.3 per cent) and an increase in those reporting no religion (from 14.8 per cent to 25.1 per cent).
........I'd also say that most people in England, at least, would be hard pressed to name most of their acquaintances' religious beliefs simply because it's not a topic of conversation which comes up all that often, regardless of what those beliefs (or lack thereof) may be.