Year	Percent
1990	88.848
1991	88.854
1992	88.906
1993	88.975
1994	89.014
1995	88.99
1996	88.91
1997	88.765
1998	88.543
1999	88.23
2000	87.825
2001	87.26
2002	86.585
2003	85.865
2004	85.204
2005	84.667
2006	84.252
2007	83.96
2008	83.745
2009	83.538
2010	83.295
2011	83.182
2012	83.091
2013	83
2014	82.928
2015	82.869
2016	82.812
2017	82.844
2018	82.815
2019	82.713
2020	82.535
2021	82.293
2022	81.979
2023	81.612
2024	81.223
2025	80.831
2026	80.45
2027	80.066
2028	79.699
2029	79.374
2030	79.106