To understand what this means, consider an investor who was unlucky enough to invest a lump sum in the stock market on the exact day of that October 2007 high. Provided he or she had the intestinal fortitude to stay with the investment through thick and thin, and reinvest all dividends along the way, the investor would now be in the black.

How long did it take?

This unlucky investor was under water for just four and one-half years. I don’t know about you, but that strikes me as remarkably little time to completely recover from what some investors have referred to as one of the worst bear markets of all time.

Some will react to this news by increasing their confidence in the long-term uptrend of the U.S. stock market. After all, if the worst case scenario — something that was considered so rare that some began referring to it as a “Black Swan” event — can be overcome in less than five years, shouldn’t we be allocating an even higher percentage of our retirement portfolios to equities?