Year	Percent
1970	0.10108
1971	0.32683
1972	0.15261
1973	0.15831
1974	0.10213
1975	0.15127
1976	0.0714
1977	0.21835
1978	0.05064
1979	0.13726
1980	0.15541
1981	0.32558
1982	0.22564
1983	0.45825
1984	0.43099
1985	0.38619
1986	0.38431
1987	0.25988
1988	0.52797
1989	0.23128
1990	0.63243
1991	0.61288
1992	0.32594
1993	0.68086
1994	0.4789
1995	0.59801
1996	0.6652
1997	0.83951
1998	0.98356
1999	0.02115
2000	0.56844
2001	1.40786
2002	0.90737
2003	0.13598
2004	0.79527
2005	2.82365
2006	3.03503
2007	5.448
2008	2.82875
2009	0.84011
2010	1.446
2011	2.27652
2012	0.32794
2013	0.95169
2014	0.94848
2015	0.87813
2016	0.81954
2017	0.34848