FACTBOX: The last 10 Dow bear markets

NEW YORK (Reuters) - The Dow Jones industrial average .DJI sank into a bear market on Wednesday -- more than 20 percent below its record high close on October 9, 2007 -- after succumbing to the pressure of a housing slump, a credit crisis, record high oil prices and a weakening economy.

Since 1900, whenever the Dow has fallen into a bear market, it has on average shed 30 percent of its value for the duration of the slump. Bear markets have tended to last just over a year.

The Dow's worst bear market occurred in the early years of the Great Depression and stretched from April 17, 1930, to July 8, 1932. The average lost 86 percent of its value in that period, falling from 294.07 to a bottom of 41.22.

The following is a recap of the previous 10 bear markets for the Dow, according to Ned Davis Research, published in "The Stock Traders Almanac 2008":

*March 19, 2002 to October 9, 2002

Dow's percentage loss: 31.5 percent

Number of days it lasted: 204

What happened? WorldCom and Enron's accounting fraud sparked fears that more firms could be artificially boosting their bottom lines.

*January 14, 2000 to September 21, 2001