Year	Percent
1960	18.17338
1961	23.535
1962	24.02686
1963	18.3856
1964	13.26109
1965	13.97287
1966	11.20693
1967	9.99758
1968	7.44867
1969	6.62115
1970	6.69135
1971	9.17072
1972	6.69782
1973	2.06195
1974	0.79218
1975	0.67899
1976	1.20531
1977	0.76692
1978	1.75903
1979	4.48896
1980	7.62264
1981	5.71628
1982	5.93369
1983	3.53566
1984	2.47966
1985	1.62219
1986	2.38359
1987	1.693
1988	1.23326
1989	0.57629
1990	3.52537
1991	4.69355
1992	0.95848
1993	0.93241
1994	0.71207
1995	0.72698
1996	0.55234
1997	0.01418
1998	0.04263
1999	0.02276
2000	0.50504
2001	0.36643
2002	0.53921
2003	0.23886
2004	0.28282
2005	0.29425
2006	0.34818
2007	0.40831
2008	0.50469
2009	0.91549
2010	0.50495
2011	1.26447
2012	1.25898
2013	1.00384
2014	1.26726
2015	0.87854
2016	1.48107
2017	1.19366
2018	0.5185
2019	0.36771
2020	0.23837
2021	0.40997