How unusual is a "bear market" for oil?

Submitted By Tim Iacono
A story in USA Today today began "Finally, investors have a bear to get excited about. Oil now is in unofficial bear market territory, with the price of a barrel of crude falling to $115.20, down 21% from its July 3 peak."

A good question to have asked prior to writing an article such as this, something that apparently doesn't occur to the new "oil bear market" enthusiasts, is whether a 20 percent decline in the price of crude oil is unusual or statistically significant in any way.

It doesn't take too much work to realize they happen just about every year.