Year	Percent
1983	68.70677
1984	68.74717
1985	69.08079
1986	68.80134
1987	72.11282
1988	68.93685
1989	65.06115
1990	69.8433
1991	68.66895
1992	69.75605
1993	69.61729
1994	64.36253
1996	61.66823
2002	59.27065
2003	59.76801
2004	59.27282
2005	63.40428
2006	62.76919
2007	64.04414
2008	64.84231
2009	63.82586
2010	66.26562
2011	66.49613
2012	66.26287
2013	67.04714
2014	67.7088
2015	66.41799
2016	66.57374
2017	66.2717