Year	Percent
1991	96.305
1992	95.791
1993	96.793
1994	98.312
1995	95.941
1996	96.688
1997	96.935
1998	96.996
1999	96.622
2000	96.31
2001	96.332
2002	95.879
2003	92.421
2004	92.202
2005	90.967
2006	90.635
2007	89.381
2008	88.193
2009	88.777
2010	88.18
2011	88.09
2012	88.017
2013	88.222
2014	87.886
2015	87.33
2016	87.874
2017	87.858
2018	87.824
2019	87.786
2020	87.746
2021	87.707
2022	87.667