Year	Percent
1965	10.89012
1966	13.60332
1967	10.08322
1968	9.27738
1969	9.22965
1970	9.38833
1971	5.64446
1972	8.8771
1973	4.67304
1974	2.54431
1975	4.0499
1976	3.75876
1977	3.75726
1978	4.12825
1979	5.93391
1980	17.7403
1981	24.15441
1982	41.57796
1983	59.17031
1984	54.30938
1985	78.96525
1986	65.8037
1987	86.14022
1988	74.11016
1989	56.84665
1990	49.36265
1991	33.53392
1992	33.13282
1993	26.93418
1994	17.48649
1995	14.94087
1996	18.61917
1997	17.24911
1998	9.19059
1999	10.13864
2000	9.24225
2001	11.62595
2002	11.54318
2003	8.6621
2004	9.53256
2005	7.99007
2006	5.5491
2007	3.0389
2008	6.70567
2009	11.82049
2010	9.83301
2011	8.24144
2012	5.80637
2013	4.51916
2014	2.64718
2015	2.38939
2016	3.3388
2017	3.63966
2018	5.30203
2019	6.14342
2020	8.02494
2021	3.50376