Year	Percent
1990	64.07
1991	64.57
1992	65.38
1993	66.19
1994	66.83
1995	67.22
1996	67.44
1997	67.57
1998	67.78
1999	67.78
2000	67.66
2001	67.39
2002	67.06
2003	66.66
2004	66.29
2005	65.98
2006	65.83
2007	65.83
2008	66
2009	66.12
2010	66.03
2011	65.59
2012	65.13
2013	64.64
2014	64.21
2015	63.91
2016	63.64
2017	63.47
2018	63.34
2019	63.19
2020	62.39