Year	Percent
1990	96.581
1991	96.567
1992	95.806
1993	94.844
1994	94.924
1995	94.856
1996	94.883
1997	94.031
1998	93.652
1999	93.215
2000	93.999
2001	94.064
2002	93.06
2003	94.175
2004	93.953
2005	93.817
2006	93.983
2007	93.105
2008	93.393
2009	93.558
2010	92.926
2011	93.484
2012	93.756
2013	93.629
2014	94.019
2015	93.599
2016	93.517
2017	93.522
2018	93.519
2019	93.508
2020	93.487
2021	93.46
2022	93.427
2023	93.391
2024	93.356
2025	93.323
2026	93.292
2027	93.263
2028	93.235
2029	93.208
2030	93.183