Year	Percent
1991	62.97
1992	64.13
1993	64.24
1994	64.27
1995	64.42
1996	63.78
1997	64.64
1998	64.32
1999	64.51
2000	63.47
2001	62.39
2002	62.1
2003	61.01
2004	60.3
2005	60.72
2006	60.06
2007	59.36
2008	60.13
2009	61.11
2010	61.7
2011	59.4
2012	58.95
2013	61.47
2014	61.88
2015	62.47
2016	61.71
2017	63.29
2018	64.87
2019	65.13
2020	54.34