The following table shows the stock prices at the end of each year, and the dividends paid at the end of each year by Fintech-Bank. What is the volatility of the period documented in the table?

Dividends Stock Price Date $16.8 31/12/2007 $1.0 $18.2 31/12/2008 $2.0 $19.6 31/12/2009 $3.0 $20.5 31/12/2010 $2.0 $19.3 31/12/2011 $2.0 $18.4 31/12/2012