Year	Percent
1990	93.225
1991	93.303
1992	93.361
1993	93.449
1994	93.31
1995	93.21
1996	93.156
1997	93.06
1998	92.884
1999	92.87
2000	92.752
2001	92.66
2002	92.536
2003	92.495
2004	92.409
2005	92.299
2006	92.198
2007	92.035
2008	91.973
2009	92.072
2010	92.009
2011	91.898
2012	91.812
2013	91.747
2014	91.667
2015	91.568
2016	91.529
2017	91.507
2018	91.49
2019	91.476
2020	91.464
2021	91.453
2022	91.443
2023	91.433
2024	91.423
2025	91.412
2026	91.4
2027	91.387
2028	91.371
2029	91.351
2030	91.326