Year	Percent
1990	74.83
1991	75.07
1992	75.36
1993	75.71
1994	75.8
1995	75.84
1996	75.8
1997	75.52
1998	75.21
1999	74.89
2000	75.44
2001	75.97
2002	76.47
2003	76.34
2004	76.66
2005	76.96
2006	77.22
2007	77.89
2008	78.1
2009	78.5
2010	79.37
2011	79.17
2012	78.52
2013	79.17
2014	80.03
2015	78.77
2016	78.72
2017	79.09
2018	78.88
2019	79.94