Year	Percent
1990	87.29
1991	87.149
1992	87.026
1993	86.886
1994	86.75
1995	86.263
1996	85.98
1997	85.829
1998	85.635
1999	84.656
2000	84.844
2001	85.724
2002	85.502
2003	85.307
2004	85.747
2005	85.573
2006	85.534
2007	85.829
2008	85.867
2009	85.968
2010	85.571
2011	85.994
2012	85.916
2013	85.214
2014	84.638
2015	83.409
2016	83.305
2017	83.315
2018	83.348
2019	83.386
2020	83.417
2021	83.44
2022	83.458
2023	83.47
2024	83.478
2025	83.484
2026	83.484
2027	83.477
2028	83.471
2029	83.478
2030	83.506