Vanguard Sht Term Govt Bond ETF - 2010  (Inactive Symbol)

The following graph plots the year-to-date performance of the stock for 2010 compared to the probability calculated by a random walk model.

Initial Value*: $57.4 Hist. Volatility: 0.09% Annual Drift: 7% Final Value*: $58.7 Percentile: 5%
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 2010 (what's this?).