Year	Percent
1984	57.64673
1986	51.01266
1987	56.335
1988	55.52687
1989	55.84591
1990	55.66437
1994	55.04456
2000	77.75056
2001	76.19787
2002	71.63561
2004	75.49006
2005	76.36212
2006	75.11357
2007	74.49898
2008	74.56477
2009	74.53767
2010	75.08238
2011	76.02238
2012	76.913
2013	77.16867
2014	77.41063
2015	76.92962
2016	76.70843
2017	76.78364