Year	Percent
1990	73.36
1991	72.99
1992	72.62
1993	72.24
1994	71.84
1995	71.42
1996	71.32
1997	71.28
1998	71.29
1999	71.37
2000	71.51
2001	71.67
2002	71.9
2003	72.18
2004	72.47
2005	72.76
2006	72.76
2007	72.76
2008	72.77
2009	72.81
2010	70.47
2011	68.32
2012	66.07
2013	66.47
2014	64.5
2015	68.61
2016	68.98
2017	69.35
2018	69.71
2019	70.04