Year	Percent
1990	65.94
1991	65.52
1992	65.88
1993	65.11
1994	66.42
1995	66.48
1996	66.54
1997	66.07
1998	66.71
1999	66.84
2000	67.24
2001	66.37
2002	65.18
2003	64.76
2004	65.04
2005	63.91
2006	64.05
2007	66.28
2008	66.64
2009	66.66
2010	67.19
2011	67.27
2012	67.73
2013	67.05
2014	66.81
2015	66.5
2016	66.18
2017	66.8
2018	67.44
2019	68.01
2020	66.45