Year	Percent
1990	93.936
1991	93.961
1992	93.992
1993	94.025
1994	93.829
1995	93.616
1996	93.395
1997	93.153
1998	92.891
1999	92.614
2000	92.326
2001	92.021
2002	91.703
2003	91.687
2004	91.678
2005	91.648
2006	91.649
2007	91.654
2008	91.641
2009	91.635
2010	91.638
2011	91.644
2012	91.652
2013	91.664
2014	91.665
2015	91.654
2016	91.637
2017	91.586
2018	91.532
2019	91.483
2020	91.446
2021	91.42
2022	91.405
2023	91.4
2024	91.4
2025	91.405
2026	91.416
2027	91.431
2028	91.449
2029	91.468
2030	91.487