Common share price of a bank over last 5 years? How would you describe how its price has changed?

and what is the most suitable index to compare it index to compare it to?
and what is the key factor behind the movement? I m specifically dealing with commonwealth bank share over past 5 years and am being asked these questions as well as using the best ratio to decide if they re over/under-valued. For a reference point… This is the chart I m looking at
http://www.bloomberg.com/quote/CBA:AU with a 5yr timeframe. Cheers
Added (1). I think i need to discuss what events/factors have influenced price and caused changes over past 5 years. And also use the chart to predict where the price will be at the end of 2015… Any guidance or helpful links would be much appreciated.

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