Year	Percent
1990	65.79
1991	65.46
1992	65.28
1993	65.1
1994	64.9
1995	64.69
1996	64.58
1997	64.5
1998	64.45
1999	64.42
2000	64.4
2001	64.39
2002	63.47
2003	63.71
2004	65.21
2005	65.21
2006	64.62
2007	65.53
2008	65.57
2009	65.46
2010	65.06
2011	64.22
2012	63.95
2013	63.72
2014	66.08
2015	66.86
2016	65.56
2017	66.54
2018	66.58
2019	66.99