Year	Percent
1998	96.6239
1999	95.72016
2000	95.65699
2001	95.17407
2002	96.65736
2003	96.00059
2004	94.18492
2005	95.11928
2006	95.48819
2007	95.6853
2008	95.60216
2009	94.66421
2010	93.73889
2011	93.7405
2012	93.36556
2013	92.90323
2014	93.29825
2015	92.95242
2016	92.59972
2017	91.41796