Year	Percent
1976	-0.21888
1977	0.31289
1978	0.40763
1979	0.44726
1980	0.39147
1981	0.27509
1982	0.2007
1983	0.2915
1984	0.29564
1985	0.36154
1986	0.52892
1987	0.88201
1988	1.18757
1989	1.15184
1990	0.82681
1991	0.94181
1992	0.98374
1993	2.50133
1994	2.53793
1995	1.85193
1996	1.98078
1997	2.57066
1998	3.10908
1999	3.30059
2000	-0.12789
2001	2.20108
2002	2.74357
2003	2.68713
2004	2.28724
2005	1.18875
2006	0.57995
2007	0.38008
2008	1.71145
2009	0.49352
2010	0.23825
2011	0.81241
2012	0.6454
2013	0.76419
2014	0.75914
2015	1.33192
2016	0.76596
2017	0.59383