Year	Percent
1991	86.48
1992	87.057
1993	87.467
1994	86.917
1995	87.204
1996	88.077
1997	87.207
1998	87.163
1999	87.285
2000	87.222
2001	86.969
2002	86.879
2003	86.857
2004	86.665
2005	86.658
2006	86.659
2007	85.964
2008	86.179
2009	86.168
2010	85.911
2011	85.975
2012	85.873
2013	85.655
2014	85.43
2015	86.104
2016	85.787
2017	85.887
2018	85.929
2019	85.857
2020	85.772
2021	85.676
2022	85.564