Year	Percent
1990	72.42
1991	72.92
1992	73.56
1993	74.17
1994	74.94
1995	75.88
1996	76.06
1997	76.22
1998	76.22
1999	76.19
2000	76.93
2001	77.65
2002	78.35
2003	78.48
2004	79.09
2005	79.43
2006	78.84
2007	79.52
2008	80.41
2009	79.64
2010	78.64
2011	77.87
2012	79.39
2013	80.31
2014	80.52
2015	81.36
2016	81.51
2017	80.99
2018	82.89
2019	83.75