Is swearing more common in lower social classes?

There is a widespread public association between swearing and social class, and many of those who criticise the habit most strongly do so because they believe it to be a 'common' and unrefined habit. It may be fair to say that many regular swearers come from anarchic or lower-class backgrounds, and that they swear primarily as a means of distancing themselves from mainstream society and affirming their position as a member of a particular social group. However, many famous swearers do not come from such backgrounds, and even English monarchs and American Presidents have been known to participate in the habit source: http://www.andrewgray.com/essays/swearing.htm