Year	Percent
1990	92.81
1991	92.07
1992	91.18
1993	90.27
1994	89.18
1995	89.92
1996	88.96
1997	88.49
1998	88.2
1999	88.15
2000	87.37
2001	87.94
2002	87.82
2003	87.86
2004	88.11
2005	88.82
2006	89.45
2007	90.05
2008	90.4
2009	90.05
2010	89.83
2011	90.3
2012	90.59
2013	90.9
2014	90.79
2015	90.92
2016	90.95
2017	91.25
2018	91.28
2019	91.25