Year	Percent
1971	11.85718
1972	6.95865
1973	3.25154
1974	11.85888
1975	4.32921
1976	0.52319
1977	-4.19392
1978	9.32122
1979	2.92801
1980	5.39533
1981	-2.53695
1982	-2.22755
1983	1.5966
1984	2.58439
1985	-2.15754
1986	-3.91406
1987	0.61049
1988	1.23322
1989	0.62484
1990	5.26127
1991	-7.38784
1992	3.74572
1993	18.97549
1994	26.28203
1995	10.50867
1996	-2.67188
1997	-1.35118
1998	1.29794
1999	3.7891
2000	1.74116
2001	0.45494
2002	4.53318
2003	2.97351
2004	0.60598
2005	0.38008
2006	10.36556
2007	3.58978
2008	-0.34453
2009	0.63418
2010	1.20205
2011	4.32377
2012	2.91406
2013	2.65783
2014	3.46338
2015	3.43905