Year	Percent
1999	88.32853
2000	89.20989
2001	88.69759
2002	88.60158
2003	87.80551
2004	87.93258
2005	88.85342
2006	88.6693
2007	88.34963
2008	88.82189
2009	88.96777
2010	88.27781
2011	88.02459
2012	88.2675
2013	88.14005
2014	88.03332
2015	87.55634
2016	87.63379
2017	88.63251