NASDAQ Composite Index - 1977

The following graph plots the year-to-date performance of the index for 1977 compared to the probability calculated by a random walk model.

Initial Value: 97.88 Hist. Volatility: 0.45% Annual Drift: 7% Final Value: 105.05 Percentile: 53.2608695652174%
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 1977 (what's this?).