Year	Percent
1991	89.239
1992	88.76
1993	89.089
1994	88.815
1995	87.437
1996	87.325
1997	87.094
1998	86.556
1999	86.515
2000	86.216
2001	86.395
2002	85.764
2003	85.336
2004	85.014
2005	85.266
2006	85.001
2007	88.394
2008	88.26
2009	88.322
2010	88.095
2011	87.817
2012	88.03
2013	87.804
2014	87.812
2015	86.198
2016	85.056
2017	84.801
2018	84.726
2019	84.654
2020	84.581
2021	84.51
2022	84.438