Year	Percent
1991	75.05
1992	75.05
1993	75.15
1994	75.09
1995	74.94
1996	74.86
1997	74.8
1998	74.72
1999	74.63
2000	74.54
2001	74.51
2002	74.38
2003	74.32
2004	74.24
2005	74.17
2006	74.24
2007	74.3
2008	74.34
2009	74.32
2010	70
2011	71.71
2012	71.76
2013	71.8
2014	71.87
2015	71.92
2016	72
2017	72.06
2018	72.1
2019	72.07
2020	69.64