Year	Percent
1991	89.455
1992	89.508
1993	89.739
1994	89.622
1995	89.178
1996	89.704
1997	89.419
1998	90.19
1999	89.797
2000	89.593
2001	90.239
2002	90.219
2003	90.118
2004	89.579
2005	90.026
2006	89.835
2007	89.603
2008	89.894
2009	89.222
2010	89.592
2011	89.126
2012	89.381
2013	88.851
2014	88.671
2015	88.343
2016	88.151
2017	88.041
2018	87.988
2019	87.931
2020	87.875
2021	87.823
2022	87.767