Year	Percent
1994	50.07
1995	51.87
1996	51.57
1997	51.55
1998	52.42
1999	54.32
2000	55.8
2001	56.67
2002	55.25
2003	55.82
2004	55.57
2005	56.32
2006	56.75
2007	56.4
2008	55.91
2009	58.48
2010	59.64
2011	59.42
2012	59.22
2013	60.86
2014	61.05
2015	60.69
2016	60.63
2017	60.13