Year	Percent
1996	85.22732
1997	84.69178
1998	85.32846
1999	85.13475
2000	85.1476
2001	85.72942
2002	85.86063
2003	85.23614
2004	86.30845
2005	86.4214
2006	86.46481
2007	86.39688
2008	86.33166
2009	86.71619
2010	86.04841
2011	86.28674
2012	86.48375
2013	86.46639
2014	86.5352
2015	86.84469
2016	86.58887
2017	86.75829