Year	Percent
1960	30.90224
1961	38.11407
1962	56.08923
1963	36.03785
1964	35.84718
1965	20.62704
1966	24.10045
1967	13.62629
1968	11.14192
1969	9.5278
1970	6.85634
1971	6.75432
1972	4.75193
1973	3.56596
1974	2.42767
1975	3.33038
1976	1.89155
1977	1.31263
1978	1.38218
1979	0.78366
1980	1.23983
1981	1.01842
1982	0.79918
1983	0.50877
1984	0.64069
1985	0.85952
1986	0.78292
1987	1.16051
1988	1.05302
1989	0.9456
1990	1.86958
1991	1.45069
1992	2.53844
1993	2.24583
1994	2.30905
1995	2.29101
1996	2.54591
1997	2.29222
1998	3.20946
1999	1.08075
2000	1.54879
2001	1.35334
2002	1.06972
2003	1.1619
2004	1.1167
2005	1.06334
2006	0.68166
2007	0.84901
2008	0.50861
2009	0.47014
2010	0.30132
2011	0.25404
2012	0.17998
2013	0.2234
2014	0.16465
2015	0.08439
2016	0.17788
2017	0.21155
2018	0.17564
2019	0.22408
2020	0.32823
2021	0.34577