Year	Percent
1991	85.998
1992	85.816
1993	85.814
1994	86.105
1995	85.882
1996	86.011
1997	86.727
1998	87.431
1999	88.759
2000	88.563
2001	88.364
2002	88.035
2003	87.861
2004	87.58
2005	87.203
2006	86.817
2007	86.433
2008	86.041
2009	85.464
2010	84.922
2011	84.37
2012	83.907
2013	83.33
2014	83.428
2015	83.074
2016	82.89
2017	83.08
2018	83.023
2019	82.991
2020	82.996
2021	83.032
2022	83.095