Year	Percent
1990	64.2
1991	64.69
1992	65.05
1993	65.19
1994	65.22
1995	65.49
1996	65.59
1997	65.94
1998	66.04
1999	65.87
2000	66.1
2001	66.31
2002	65.96
2003	65.63
2004	66.47
2005	66.99
2006	67.85
2007	67.46
2008	67.4
2009	67.18
2010	67.13
2011	67
2012	66.57
2013	66.73
2014	66.73
2015	66.67
2016	66.18
2017	65.62
2018	64.68
2019	62.51