Year	Percent
1990	74.39
1991	74.58
1992	75.3
1993	75.99
1994	76.7
1995	77.29
1996	77.03
1997	77.03
1998	77.24
1999	77.71
2000	77.98
2001	77.76
2002	77.94
2003	78.32
2004	78.56
2005	78.51
2006	78.82
2007	79.75
2008	80.07
2009	80.25
2010	80.69
2011	80.92
2012	81.86
2013	81.75
2014	82.59
2015	82.66
2016	82.71
2017	82.85
2018	83.08
2019	83.08