An Exceptional (note Canadian understatement) Year in the Stock Market

Economist Greg Mankiw posted a histogram chart of the S&P 500's returns this year compared to every year since 1825 that dramatically conveys how unusual it has been so far. The only year as bad as 2008 is 1931, the depths of the great depression. Of course, the year isn't over yet but how much stock market recovery can we hope for as the downward slide of the economy continues apace?