Year	Percent
1983	86.83055
1984	88.78778
1985	89.20665
1986	89.86695
1987	89.78495
1988	90.14409
1989	89.52475
1990	89.01057
1991	89.60691
1992	90.00686
1993	89.42017
1994	90.52259
1995	90.30046
1996	90.11034
1997	89.84314
1998	89.88687
1999	89.69976
2000	90.20628
2001	89.91604
2002	89.92149
2003	90.03261
2004	90.34121
2005	89.91805
2006	89.84105
2007	89.46029
2008	89.2966
2009	88.5808
2010	89.13976
2011	89.1961
2012	89.32167
2013	89.62816
2014	89.60041
2015	89.58538
2016	89.46035
2017	90.17581