Year	Percent
1990	97.536
1991	97.485
1992	97.443
1993	97.388
1994	97.328
1995	97.245
1996	97.149
1997	97.072
1998	97.185
1999	97.117
2000	97.014
2001	97.013
2002	96.949
2003	96.879
2004	96.794
2005	96.731
2006	96.668
2007	96.539
2008	96.187
2009	96.504
2010	96.409
2011	96.548
2012	96.65
2013	96.784
2014	96.603
2015	96.572
2016	96.346
2017	96.353
2018	96.362
2019	96.37
2020	96.375
2021	96.378
2022	96.379
2023	96.377
2024	96.374
2025	96.369
2026	96.362
2027	96.353
2028	96.341
2029	96.325
2030	96.305