Year	Percent
1990	86.59
1991	86.4
1992	86.29
1993	86.29
1994	86.34
1995	86.38
1996	86.45
1997	85.85
1998	87.69
1999	87.49
2000	87.89
2001	88.15
2002	88.76
2003	87.77
2004	88.76
2005	88.78
2006	89.03
2007	89.27
2008	90.05
2009	89.66
2010	90.02
2011	90.15
2012	90.75
2013	90.69
2014	90.33
2015	90.79
2016	90.48
2017	91.89
2018	92.05
2019	92.43