NYSE Composite Index - 1993

The following graph plots the year-to-date performance of the index for 1993 compared to the probability calculated by a random walk model.

Initial Value: 2539.92 Hist. Volatility: 0.44% Annual Drift: 7% Final Value: 2739.44 Percentile: 57%
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 1993 (what's this?).