Year	Percent
1990	76.79
1991	76.77
1992	76.88
1993	76.89
1994	76.84
1995	76.81
1996	76.67
1997	76.16
1998	75.98
1999	75.84
2000	75.59
2001	75.7
2002	75.77
2003	76.1
2004	76.16
2005	76.25
2006	76.38
2007	76.5
2008	76.63
2009	76.73
2010	76.74
2011	76.71
2012	76.63
2013	76.5
2014	76.38
2015	76.23
2016	77.71
2017	77.49
2018	77.28
2019	77.08