Here's another chart from Praveen Chawla. It shows an apparent correlation between bear market declines and length of time it takes to recover to the pre-bear high. Each data point represents the year in which a bear ends. The underlying price levels are nominal (not adjusted for inflation), and the recovery level does not include reinvested dividends.

The curved line is a polynomial regression drawn by Excel to mark the best fit through the data points. The estimated for the current bear recovery is a guess based on the regression using the March low.

Of course, this isn't a crystal ball. The teddy bear that took so long to end in 1885 was a clear outlier. Perhaps the data point for our current market will ultimately be an outlier on the other side.

Interesting stuff!