Year	Percent
1985	63.05179
1987	62.40429
1988	56.59502
1989	54.24954
1990	53.05883
1991	49.95437
1992	49.15718
1993	47.87056
1994	42.40483
1995	38.23404
1996	40.72836
1997	41.21943
1998	43.45984
1999	41.28114
2000	43.19424
2001	39.83107
2002	39.36328
2003	44.28653
2004	44.94108
2005	44.70814
2006	50.83904
2007	62.65929
2008	64.29232
2009	50.33597
2010	40.67138
2011	48.68536
2012	50.41507
2013	63.33907
2014	64.06465
2015	74.30378
2016	57.48459
2017	59.22805