Year	Percent
1995	37.14462
1996	41.94043
1997	44.96675
1998	39.12476
1999	32.41433
2000	38.54566
2001	44.04264
2002	47.34211
2003	46.16972
2004	47.34668
2005	53.84224
2006	55.62027
2007	50.35831
2008	57.13901
2009	51.9392
2010	65.34215
2011	74.99541
2012	81.62313
2013	84.06226
2014	81.10314
2015	75.83685
2016	74.45145
2017	81.30795