Year	Percent
1990	83.59
1991	83.461
1992	83.32
1993	83.577
1994	83.821
1995	84.052
1996	84.278
1997	84.49
1998	85.481
1999	86.278
2000	86.474
2001	86.726
2002	86.939
2003	87.086
2004	87.16
2005	87.173
2006	86.802
2007	86.379
2008	85.877
2009	86.2
2010	85.813
2011	85.924
2012	86.023
2013	86.106
2014	85.739
2015	84.686
2016	83.787
2017	83.693
2018	83.595
2019	83.51
2020	83.449
2021	83.414
2022	83.405
2023	83.407
2024	83.392
2025	83.348
2026	83.281
2027	83.188
2028	83.084
2029	82.992
2030	82.925