Year	Percent
1990	87.65
1991	87.7
1992	87.77
1993	87.89
1994	88
1995	88.1
1996	88.11
1997	88.13
1998	88.08
1999	88.13
2000	88.19
2001	88.02
2002	87.91
2003	87.86
2004	87.83
2005	87.75
2006	87.53
2007	87.37
2008	87.2
2009	87.11
2010	86.99
2011	86.9
2012	85.45
2013	83.79
2014	81.85
2015	81.86
2016	81.83
2017	81.83
2018	81.83
2019	81.87