Year	Percent
1995	91.48984
1996	91.35681
1997	91.55177
1998	91.24383
1999	91.1206
2000	91.10762
2001	91.01011
2002	90.7758
2003	90.8898
2004	91.00288
2005	90.99794
2006	90.78264
2007	90.35621
2008	90.48746
2009	90.34639
2010	90.0399
2011	90.52986
2012	90.50215
2013	90.3005
2014	90.39627
2015	90.36551
2016	90.4864
2017	90.49503