Year	Percent
1972	0.45659
1973	0.02704
1974	1.33635
1975	5.01871
1976	2.70053
1977	6.5812
1978	6.38108
1979	13.46212
1980	4.88031
1981	6.488
1982	-2.53551
1983	-1.01826
1984	1.01441
1985	3.22739
1986	6.9277
1987	9.63576
1988	7.30958
1989	9.64009
1990	2.70102
1991	7.10421
1992	6.79553
1993	5.29916
1994	4.4573
1995	3.0463
1996	1.3549
1997	-0.89206
1998	9.68483
1999	6.3487
2000	5.21592
2001	1.90149
2002	6.48956
2003	-2.73891
2004	2.51191
2005	-1.44268
2006	3.67724
2007	1.08071
2008	3.20967
2009	1.83515
2010	3.05626
2011	2.04768
2012	0.54894
2013	1.79336
2014	0.58901
2015	0.78348
2016	0.7217
2017	-1.3488