Year	Percent
1990	63.51
1991	63.52
1992	63.52
1993	63.51
1994	63.51
1995	63.56
1996	63.58
1997	63.67
1998	63.79
1999	63.88
2000	63.97
2001	64.12
2002	64.29
2003	64.43
2004	64.61
2005	64.41
2006	64.22
2007	64.01
2008	63.79
2009	63.56
2010	63.33
2011	63.13
2012	68.16
2013	63.19
2014	63.68
2015	63.41
2016	63.97
2017	64.16
2018	64.44
2019	64.71