Year	Percent
1996	83.93352
1997	83.22128
1998	83.85556
1999	83.41507
2000	83.11499
2001	83.73133
2002	83.95059
2003	83.32183
2004	84.15437
2005	84.67924
2006	84.91629
2007	85.09669
2008	84.53907
2009	85.2125
2010	84.20169
2011	84.41503
2012	84.72055
2013	84.77106
2014	84.96963
2015	85.57007
2016	85.10165
2017	85.28098