Year	Percent
1976	67.24627
1977	69.44444
1978	69.72091
1979	69.35104
1980	69.52967
1981	59.48681
1982	60.09081
1983	58.97875
1984	60.55613
1985	63.39945
1986	60.70462
1987	62.94858
1988	58.18021
1989	59.78501
1990	55.23359
1991	55.08308
1992	53.82676
1993	50.86333
1994	60.13255
1995	60.68344
1996	60.10319
1997	60.78951
1998	60.64099
1999	60.1959
2000	50.49771
2001	51.68503
2002	48.88395
2003	46.4394
2004	62.48733
2005	63.213
2006	65.89415
2007	67.95302
2008	67.6159
2009	70.33745
2010	68.48615
2011	63.89121
2012	67.53952
2013	69.72958
2014	69.11715
2015	70.55345
2016	70.96368