Year	Percent
1983	53.45819
1984	50.95981
1985	50.45731
1986	51.12207
1987	50.4553
1988	53.75596
1989	55.43223
1990	56.1491
1991	55.95351
1992	58.40218
1993	62.9688
1994	64.07807
1995	62.4649
1996	63.43845
1997	58.1741
1998	58.11155
1999	59.87812
2000	61.05831
2001	61.11614
2002	59.63765
2003	55.25268
2004	53.43073
2005	56.7127
2006	56.79312
2007	56.87565
2008	57.63983
2009	58.37416
2010	58.24427
2011	58.29099
2012	59.33905
2013	59.10286
2014	59.09566
2015	59.32547
2016	59.6925
2017	61.24876