Year	Percent
1990	62.51
1991	61.86
1992	61.78
1993	61.56
1994	62.05
1995	63.12
1996	64.4
1997	65.89
1998	66.89
1999	66.64
2000	66.93
2001	66.89
2002	67.09
2003	65.81
2004	65.72
2005	65.43
2006	65.69
2007	66.4
2008	67.42
2009	66.44
2010	65.69
2011	65.2
2012	65.3
2013	65
2014	64.72
2015	64.89
2016	64.37
2017	63.6
2018	63.93
2019	64.07
2020	63.73