Year	Percent
1970	0.86065
1971	0.41611
1972	0.29896
1973	0.68981
1974	0.78767
1975	0.52645
1976	1.33462
1977	1.25813
1978	0.64887
1979	1.34752
1980	1.087
1981	0.2064
1982	0.20214
1983	0.39702
1984	0.17368
1985	0.47018
1986	0.45207
1987	0.49407
1988	0.00472
1989	0.7508
1990	0.66587
1991	0.23101
1992	0.07751
1993	2.53235
1994	0.10398
1995	0.46747
1996	0.90216
1997	0.47345
1998	0.18837
1999	0.40286
2000	0.8729
2001	0.04083
2002	0.21006
2003	0.54841
2004	0.28619
2005	0.1132
2006	0.19622
2007	2.28124
2008	0.26629
2009	0.31403
2010	0.44516
2011	3.45722
2012	2.74199
2013	2.03066
2014	1.33599
2015	0.96821
2016	0.555
2017	0.89606