According to an article from The Cincinnati Enquirer(1), irrational fear of 13 is the nation's favorite superstition. It is estimated that fear of 13 costs the U.S. $1 billion a year in reduced business, absenteeism and travel cancellations. The column also notes that hotels and hospitals often have no Room 13, more than 80% of skyscrapers lack a 13th floor, and many cities have no 13th Street. This year Friday the 13th occurs twice -- today and in October. Read more here(2).
Illustration: Octavio Diaz

1. http://news.enquirer.com/apps/pbcs.dll/article?AID=/20060113/NEWS01/601130402
2. http://news.enquirer.com/apps/pbcs.dll/article?AID=/20060113/NEWS01/601130402