Year	Percent
1990	62.2
1991	62.07
1992	61.97
1993	61.93
1994	61.96
1995	62.08
1996	62.27
1997	62.53
1998	62.83
1999	63.12
2000	63.37
2001	63.53
2002	63.68
2003	63.81
2004	63.95
2005	64.11
2006	64.21
2007	64.32
2008	64.45
2009	64.6
2010	64.71
2011	64.78
2012	64.81
2013	64.82
2014	64.81
2015	64.81
2016	64.78
2017	64.79
2018	64.81
2019	64.83