Year	Percent
1990	83
1991	83
1992	83.02
1993	82.89
1994	82.85
1995	83.51
1996	84.18
1997	84.85
1998	85.5
1999	86.13
2000	86.73
2001	87.31
2002	87.87
2003	88.41
2004	88.92
2005	89.41
2006	89.38
2007	89.34
2008	89.29
2009	89.24
2010	89.2
2011	89.16
2012	89.13
2013	89.1
2014	89.25
2015	89.39
2016	89.49
2017	89.58
2018	89.69
2019	89.77