Year	Percent
1990	94.53
1991	94.592
1992	94.691
1993	95.007
1994	94.721
1995	94.549
1996	94.297
1997	93.931
1998	93.91
1999	93.787
2000	93.741
2001	93.786
2002	93.819
2003	93.726
2004	93.704
2005	93.713
2006	93.701
2007	93.199
2008	92.637
2009	92.005
2010	91.292
2011	90.487
2012	90.448
2013	90.418
2014	90.336
2015	90.253
2016	90.168
2017	90.133
2018	90.098
2019	90.06
2020	90.016
2021	89.967
2022	89.915
2023	89.859
2024	89.795
2025	89.724
2026	89.646
2027	89.562
2028	89.475
2029	89.39
2030	89.309