Year	Percent
1990	30.04775
1991	29.60329
1992	36.53659
1993	32.13194
1994	27.65358
1995	30.99728
1996	35.14477
1997	36.99165
1998	34.95475
1999	39.10169
2000	42.53534
2001	43.4649
2002	46.15369
2003	48.53901
2004	50.76961
2005	58.5
2006	65.2
2007	66.1
2008	65.7
2009	56.4
2010	59.8
2011	61.8
2012	59.45579
2013	57.05442
2014	53.6
2015	45
2016	47.5
2017	49.58216