Year	Percent
1990	78
1991	77.98
1992	78
1993	77.87
1994	77.9
1995	77.84
1996	77.83
1997	77.88
1998	77.92
1999	77.93
2000	77.9
2001	77.82
2002	77.7
2003	77.57
2004	77.46
2005	77.4
2006	77.41
2007	77.44
2008	77.48
2009	77.52
2010	77.56
2011	77.61
2012	77.64
2013	77.65
2014	77.46
2015	77.28
2016	77.05
2017	76.83
2018	76.62
2019	76.35
2020	75.24