Year	Percent
1965	14.39554
1966	13.48582
1967	14.52632
1968	10.8515
1969	12.66982
1970	24.74854
1971	24.43259
1972	24.74005
1973	26.41362
1974	32.207
1975	32.91604
1976	34.01449
1977	38.01268
1978	38.73747
1979	41.96783
1980	45.6009
1981	49.83902
1982	47.43985
1983	42.71978
1984	44.32818
1985	38.13317
1986	37.30239
1987	35.81571
1988	41.65762
1989	47.6616
1990	50.60421
1991	45.3204
1992	46.465
1993	47.96563
1994	47.87211
1995	48.8101
1996	43.61098
1997	41.38663
1998	41.45967
1999	39.92607
2000	42.90922
2001	46.73523
2002	44.55707
2003	42.90666
2004	44.72715
2005	45.31896
2006	47.91084
2007	52.98936
2008	59.22183
2009	48.53555
2010	55.27853
2011	56.55568
2012	58.60884
2013	57.06103
2014	56.57012
2015	51.61087
2016	51.05381
2017	56.09844