Year	Percent
1975	8.05301
1976	2.98172
1977	9.79505
1978	6.69405
1979	12.37105
1980	22.93755
1981	12.19233
1982	9.86738
1983	5.64764
1984	5.20043
1985	3.52511
1986	4.4601
1987	7.32629
1988	2.76601
1989	6.74071
1990	3.80186
1991	3.22468
1992	3.92836
1993	4.22624
1994	1.28774
1995	3.0829
1996	2.52606
1997	0.953
1998	8.73192
1999	4.37029
2000	0.73354
2001	2.29982
2002	0.89181
2003	1.09649
2004	5.83167
2005	6.63149
2006	3.08667
2007	4.64283
2008	1.74517
2009	0.24965
2010	0.32149
2011	3.73966
2012	-0.39643
2013	-0.94172
2014	-0.08997
2015	-1.41242
2016	-3.13918
2017	4.17207