Year	Percent
1998	91.33057
1999	92.54558
2000	93.76071
2001	92.48755
2002	92.34622
2003	92.01724
2004	92.64503
2005	92.46778
2006	91.75795
2007	92.09243
2008	92.25485
2009	92.85808
2010	93.94427
2011	93.98821
2012	93.51732
2013	92.48838
2014	92.48168
2015	92.10676
2016	91.173
2017	91.43134