Year	Percent
1990	65.2
1991	65.2
1992	65.4
1993	65.67
1994	65.99
1995	66.36
1996	66.52
1997	66.76
1998	67.11
1999	67.54
2000	68
2001	67.76
2002	67.39
2003	67.18
2004	67.11
2005	67.11
2006	66.81
2007	66.56
2008	66.41
2009	66.39
2010	66.43
2011	66.42
2012	66.34
2013	66.21
2014	66.04
2015	65.87
2016	65.67
2017	65.46
2018	66.58
2019	64.72
2020	63.92