Year	Percent
1990	69.51
1991	69.66
1992	70.16
1993	70.52
1994	70.7
1995	70.99
1996	71.28
1997	71.68
1998	72.01
1999	72.31
2000	72.57
2001	71.71
2002	72.85
2003	72.26
2004	71.34
2005	71.36
2006	73.13
2007	72.71
2008	73.33
2009	71.82
2010	73.38
2011	74.98
2012	75.96
2013	76.73
2014	76.94
2015	79.48
2016	79.42
2017	79.5
2018	81.74
2019	82.92