Year	Percent
1991	84.928
1992	84.544
1993	84.297
1994	83.923
1995	83.939
1996	83.718
1997	83.562
1998	83.337
1999	85.294
2000	85.111
2001	84.878
2002	85.105
2003	84.927
2004	84.888
2005	84.428
2006	83.922
2007	83.335
2008	82.838
2009	81.994
2010	81.549
2011	75.239
2012	74.604
2013	73.746
2014	72.991
2015	72.331
2016	71.356
2017	71.157
2018	71.054
2019	70.955
2020	70.859
2021	70.764
2022	70.67