Year	Percent
1990	65.98
1991	66.14
1992	66.23
1993	66.25
1994	66.23
1995	66.16
1996	66.2
1997	66.17
1998	66.11
1999	66.01
2000	65.87
2001	65.86
2002	65.75
2003	65.64
2004	65.47
2005	65.25
2006	65.21
2007	65.06
2008	64.92
2009	64.83
2010	64.63
2011	64.49
2012	64.32
2013	64.17
2014	64
2015	63.84
2016	63.55
2017	63.29
2018	63.11
2019	62.96