Year	Percent
1990	65.44
1991	65.06
1992	65.33
1993	65.23
1994	65.68
1995	65.83
1996	66
1997	66.33
1998	66.3
1999	66.36
2000	66.42
2001	66.05
2002	65.7
2003	65.3
2004	65.02
2005	65.04
2006	65.15
2007	64.97
2008	64.97
2009	64.31
2010	63.57
2011	63
2012	63.05
2013	62.5
2014	62.2
2015	62.01
2016	62.16
2017	62.29
2018	62.31
2019	62.57
2020	61.41