Year	Percent
1998	94.85706
1999	93.73073
2000	93.90691
2001	93.12574
2002	94.43134
2003	93.99876
2004	93.47477
2005	93.57201
2006	93.70257
2007	93.61907
2008	93.44978
2009	92.48592
2010	92.26574
2011	92.35931
2012	92.01398
2013	91.47855
2014	91.42726
2015	90.66433
2016	90.25048
2017	89.89332