Year	Percent
1984	92.89791
1992	91.91946
1993	91.8411
1994	92.26891
1995	92.51718
1996	92.67434
1997	92.65653
1998	92.13706
1999	92.39545
2000	92.36406
2001	93.11242
2002	93.43028
2003	93.39104
2004	93.06099
2005	93.60082
2006	93.90211
2007	93.67985
2008	93.41007
2009	93.27913
2010	93.04926
2011	93.09021
2012	93.19677
2013	92.61558
2014	92.83038
2015	92.75154
2016	92.67435
2017	93.05282