Year	Percent
1991	61.11
1992	61.02
1993	59.33
1994	59.33
1995	60.78
1996	60.92
1997	62.23
1998	62.16
1999	62.78
2000	62.83
2001	62.68
2002	63.27
2003	61.98
2004	62.58
2005	62.68
2006	63.67
2007	63.35
2008	62.75
2009	60.26
2010	58.58
2011	58.15
2012	57.44
2013	56.83
2014	56.92
2015	57.28
2016	57.72
2017	57.9
2018	58.46
2019	59.09
2020	58.41