I had the answer, but by the time I got through all the obstacle course to get allowed to post, the question was deleted. I thought I read delete didn’t really work.
Go here: http://boards.straightdope.com/sdmb/showthread.php?threadid=36168
It wasn’t deleted, it was moved into the General Questions forum, because it was, well, a general question. While neither you nor I can move or delete threads and posts, we have moderators to take care of what needs to be done. Tuba Diva is the moderator of this forum, and she saw the thread, and put it where it should have been.