Year	Percent
1983	66.53562
1984	64.22151
1985	65.45777
1986	63.12819
1987	68.48109
1988	63.77305
1989	61.14378
1990	67.86281
1991	66.18382
1992	69.02444
1993	64.66261
1994	60.1967
1996	57.13527
2002	54.60548
2003	56.14836
2004	56.30826
2005	61.6439
2006	59.29186
2007	60.78572
2008	60.38577
2009	59.63389
2010	61.7953
2011	63.90632
2012	62.66827
2013	64.52922
2014	64.89713
2015	64.14788
2016	63.44701
2017	63.02157