While some people (think Taylor Swift) consider the number 13 lucky, for most it seems to indicate dire news or events especially, when it falls on a Friday. Today, happens to be that day. What's worse is that while most years have only one such day, 2012 has three. The first one was January 13th and the grand finale will be July 13th. So does that mean we are in for triple trouble?

While of most of us will probably shrug that thought off, there are over 20 million Americans and probably scores more worldwide, that fear the day so much, that their phobia has even been given a name - friggatriskaidekaphobiacs.

Not surprisingly, this group comprises of people like construction workers and ship builders, who are subject to all kinds of injury risks on a day-to-day basis, and probably fear that the risks get exacerbated when the 13th falls on a Friday. So how did this date and day of the week acquire such a bad reputation? While nobody knows for sure, here are a few theories.

First of all there is the irrational fear of the number 13 - While most people fear just Friday the 13th, some, called Triskaidekaphobiacs are afraid of the number, no matter what it is associated with.

According to Donald Dossey, a folklore historian, the fear of the number can be traced all the way back to ancient times, when the Vikings inhabited Scandinavia.

12 gods were having a dinner party at Valhalla, the Viking's mythological heaven. Suddenly, an uninvited guest, the mischievous god Loki walked in and instigated Hoder, the blind god of darkness to shoot Balder, the god of joy and gladness.

The Friday part is also rooted in ancient mythology and religion - According to the bible, Jesus was crucified on a Friday. Though the date is not believed to be the 13th, it was following the Last Supper, which happened to be attended by 13 men that included Judas Iscariot, the apostle who betrayed Jesus. Other biblical scholars maintain that this was the day when Eve tempted Adam with the forbidden fruit - Again, the date is a little hazy. The one bad event that is believed to have happened on Friday the 13th, was the slaying of Abel by his brother Cain (The sons of Adam and Eve).

So how bad is the fear? Experts estimate that businesses lose between $800-$900mm USD on this day because people avoid traveling, going to work and even, shopping! Are you superstitious about this day? If so, be sure to add your comments below.

Resources: shorenewstoday.com, urbanlegends.about.com, nationalgeographic.com, vancouversun.com