Year	Percent
1960	21.97309
1961	18.66667
1962	22.94372
1963	20.78431
1964	15.69343
1965	12.5
1966	12.8125
1967	10.08902
1968	10.72386
1969	10.55156
1970	7.76942
1993	32.66718
1994	38.67607
1995	46.58255
1996	43.79756
1997	45.31771
1998	44.38133
1999	53.6327
2000	61.36251
2001	61.20223
2002	64.2708
2003	66.56034
2004	70.90552
2005	72.74722
2006	76.02121
2007	72.94218
2008	67.77701
2009	55.91771
2010	59.52094
2011	59.50109
2012	62.70767
2013	67.65855
2014	67.00876
2015	66.14564
2016	65.6685
2017	64.16076