Year	Percent
1990	88.31
1991	88.31
1992	88.36
1993	88.41
1994	88.49
1995	88.55
1996	88.59
1997	88.63
1998	88.66
1999	88.72
2000	88.8
2001	88.88
2002	88.96
2003	89.04
2004	89.11
2005	89.17
2006	89.22
2007	88.75
2008	88.25
2009	87.73
2010	87.19
2011	86.62
2012	86.03
2013	85.42
2014	84.78
2015	84.13
2016	84.15
2017	84.09
2018	84.07
2019	84.04