Year	Percent
1990	72.85
1991	72.85
1992	72.9
1993	72.89
1994	72.84
1995	72.76
1996	72.77
1997	72.7
1998	72.62
1999	72.54
2000	72.52
2001	72.53
2002	72.52
2003	72.57
2004	72.53
2005	72.54
2006	72.64
2007	72.73
2008	72.8
2009	72.77
2010	72.71
2011	72.85
2012	72.88
2013	73.19
2014	73.09
2015	72.9
2016	72.67
2017	72.4
2018	72.11
2019	71.81
2020	70.51