Year	Percent
1990	89.19
1991	87.78
1992	88.49
1993	89.3
1994	90
1995	90.88
1996	89.62
1997	90.21
1998	90.23
1999	90.24
2000	90.25
2001	90.28
2002	90.31
2003	90.34
2004	90.83
2005	90.82
2006	90.79
2007	90.73
2008	90.66
2009	90.57
2010	89.93
2011	90.02
2012	90.03
2013	90.09
2014	89.05
2015	89.59
2016	89.52
2017	89.6
2018	89.66
2019	89.72