Year	Percent
1990	76.73
1991	76.28
1992	75.39
1993	75.15
1994	74.97
1995	74.7
1996	74.6
1997	74.89
1998	75.26
1999	75.85
2000	76.18
2001	76.35
2002	77.42
2003	78.19
2004	78.16
2005	77.77
2006	77.75
2007	78.33
2008	78.46
2009	78.02
2010	77.91
2011	77.84
2012	77.82
2013	78.02
2014	77.74
2015	77.95
2016	78.09
2017	78.46
2018	78.47
2019	79.04