Year	Percent
1990	65.03
1991	64.52
1992	64.61
1993	64.85
1994	65.19
1995	65.54
1996	65.27
1997	65.06
1998	65.05
1999	65.31
2000	65.79
2001	65.86
2002	66.13
2003	66.76
2004	67.64
2005	68.61
2006	69.05
2007	69.72
2008	70.56
2009	71.43
2010	72.22
2011	71.41
2012	71.48
2013	71.49
2014	71.55
2015	71.64
2016	72.06
2017	72.6
2018	73.16
2019	73.59
2020	72.64