Volatility is measurement of the change in price over a given period. It is often expressed as a percentage and computed as the annualized standard deviation of the percentage change in daily price.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Yearly Average
1986									10.1	8.9	5.4	9.1	8.4
1987	8.2	15.5	10.2	9.8	10.4	10.1	14.0	48.6	42.1	48.5	39.1	35.6	24.3
1988	28.4	29.0	37.9	41.5	48.6	47.9	27.4	30.1	20.1	16.5	11.8	8.6	29.0
1989	14.5	6.0	8.2	18.7	12.0	17.9	16.1	20.4	19.1	17.2	15.6	15.2	15.1
1990	21.3	12.7	16.5	11.6	27.5	14.3	12.2	12.5	26.1	16.7	13.7	14.9	16.7
1991	19.1	15.4	10.4	7.35	15.4	22.6	15.6	10.1	10.0	16.1	11.2	6.5	13.3
1992	6.8	13.8	11.8	11.5	9.9	9.7	7.3	14.5	8.6	8.5	6.7	7.4	9.7
1993	14.9	20.5	24.4	23.8	14.1	27.0	29.9	20.9	30.1	21.2	21.9	15.7	21.5
1994	26.8	24.9	27.0	33.1	39.7	38.6	33.6	33.9	24.2	19.6	21.9	23.8	28.9
1995	26.4	17.7	14.7	10.9	26.5	30.8	19.9	20.9	30.1	23.2	21.9	15.7	21.5
1996	20.9	15.3	19.4	25.3	18.2	12.8	14.4	18.1	13.4	8.7	10.3	10.8	15.6
1997	13.1	22.3	18.4	19.1	17.4	15.8	24.6	12.4	15.3	15.9	13.4	10.5	16.5
1998	15.6	9.5	16.1	14.3	18.2	20.0	20.0	21.5	17.9	10.6	14.6	15.3	16.1
1999	20.1	17.9	31.3	27.1	23.2	23.7	25.5	26.4	20.4	17.7	25.3	19.7	23.2
2000	22.4	16.7	24.1	17.3	17.6	27.4	25.2	42.9	30.7	20.4	13.6	12.5	22.6
2001	22.2	20.7	25.4	21.5	28.4	66.8	17.3	26.7	26.3	20.9	28.4	35.2	28.3
2002	26.1	21.2	19.8	19.9	26.7	37.0	36.4	38.3	25.1	22.9	20.5	22.5	26.4
2003	25.2	28.8	23.9	41.5	34.8	29.7	41.4	29.8	17.5	30.2	33.1	20.3	29.7
2004	28.4	26.3	32.7	23.8	30.8	38.1	28.9	34.1	26.8	22.0	22.2	24.7	28.2
2005	21.9	29.6	23.5	24.9	19.9	20.2	21.3	24.2	22.7	19.7	16.3	18.2	21.9
2006	18.5	16.2	24.8	10.8	21.6	26.5	16.1	35.3	16.7	17.5	11.2	9.8	18.8
2007	13.8	19.0	24.6	12.5	21.9	21.6	18.0	13.9	13.5	12.2	20.8		17.4
Mean	19.8	19.0	21.2	20.3	23.0	26.6	22.1	25.5	21.1	20.0	18.9	17.3	21.2
High	28.4	29.6	37.9	41.5	48.6	66.8	41.4	48.6	42.1	48.5	39.1	35.6	66.8
Low	6.8	6.0	8.2	7.5	9.9	9.7	7.3	10.1	8.6	8.5	5.4	6.5	5.4