Year	Percent
1991	88.231
1992	88.389
1993	88.365
1994	88.353
1995	87.94
1996	87.47
1997	86.919
1998	86.345
1999	85.803
2000	86.247
2001	86.669
2002	87.083
2003	87.498
2004	87.925
2005	88.323
2006	88.166
2007	87.993
2008	87.799
2009	87.593
2010	87.363
2011	87.148
2012	86.938
2013	86.81
2014	86.237
2015	85.663
2016	85.118
2017	85.096
2018	85.091
2019	85.098
2020	85.116
2021	85.141
2022	85.181