Stocks: How often does a 'correction' become a bear market?

[xchrom]

http://latimesblogs.latimes.com/money_co/2011/08/stock-market-correction-bear-market-wall-street-birinyi.html

Stocks’ brutal sell-off on Thursday pushed most major market indexes into “correction” territory -- meaning, a drop of more than 10% from their recent highs.

The Standard & Poor’s 500 index (charted below) plunged 4.8% for the day and is down 12% from its 2011 high reached in April.

If the selling goes on, and the S&P and other indexes fall more than 20% from their highs, Wall Street will declare that a new bear market has begun.

So how often does a 10% correction lead into a bear market?

[Tunkamerica]

1. So if post-1962 history is a guide

So if post-1962 history is a guide, “There is a 64% probability that this is only a correction and not the start of a bear market.” Why post-1962? did i miss that?

[xchrom]

2. I don't know why '62. A rules change? Nt

[Tunkamerica]

3. Probably... If you add anything before 1962 then the theory is bullshit