Year	Percent
1996	86.88092
1997	86.54925
1998	87.17464
1999	87.26663
2000	87.69626
2001	88.18708
2002	88.14102
2003	87.52782
2004	88.88045
2005	88.47908
2006	88.29219
2007	87.93835
2008	88.41113
2009	88.45425
2010	88.21938
2011	88.48527
2012	88.54082
2013	88.42191
2014	88.31729
2015	88.2982
2016	88.27979
2017	88.45027