Year	Percent
1990	74.02
1991	74.03
1992	74.06
1993	74.29
1994	74.45
1995	74.08
1996	73.67
1997	73.25
1998	73.82
1999	74.37
2000	74.91
2001	75.22
2002	75.53
2003	75.83
2004	76.11
2005	76.4
2006	76.69
2007	76.98
2008	77.25
2009	77.5
2010	77.74
2011	77.95
2012	78.16
2013	81.11
2014	81.67
2015	80.71
2016	79.64
2017	78.76
2018	77.69
2019	77.8