Dow Jones Industrial Average - 1987

The following graph plots the year-to-date performance of the index for 1987 compared to the probability calculated by a random walk model.

Initial Value: 1895.95 Hist. Volatility: 1.23% Annual Drift: 7% Final Value: 1938.83 Percentile: 47%
Click on the image for the high resolution version.

The high to date and low to date prices of the stock plotted against a random walk model for 1987 (what's this?).