Year	Percent
1990	92.397
1991	92.458
1992	92.453
1993	92.415
1994	92.36
1995	92.228
1996	92.063
1997	91.895
1998	91.715
1999	91.493
2000	91.258
2001	91.072
2002	90.849
2003	90.598
2004	90.4
2005	90.172
2006	89.841
2007	89.537
2008	89.228
2009	88.981
2010	88.769
2011	88.591
2012	88.367
2013	88.119
2014	87.949
2015	87.833
2016	87.836
2017	87.81
2018	87.79
2019	87.773
2020	87.758
2021	87.743
2022	87.728
2023	87.712
2024	87.687
2025	87.652
2026	87.607
2027	87.554
2028	87.49
2029	87.415
2030	87.328