Year	Percent
1990	86.775
1991	86.784
1992	86.788
1993	86.646
1994	86.212
1995	86.093
1996	85.871
1997	85.732
1998	85.66
1999	85.592
2000	85.475
2001	85.439
2002	85.378
2003	85.258
2004	85.193
2005	85.226
2006	85.341
2007	85.541
2008	85.784
2009	85.979
2010	86.108
2011	86.204
2012	86.243
2013	86.224
2014	86.186
2015	86.133
2016	86.053
2017	86.035
2018	86.01
2019	85.978
2020	85.941
2021	85.904
2022	85.868
2023	85.833
2024	85.803
2025	85.78
2026	85.77
2027	85.766
2028	85.772
2029	85.791
2030	85.823