Year	Percent
1990	95.898
1991	95.99
1992	96.068
1993	95.701
1994	95.539
1995	95.247
1996	94.669
1997	94.612
1998	94.443
1999	93.702
2000	93.285
2001	92.509
2002	91.79
2003	91.461
2004	91.571
2005	91.543
2006	91.494
2007	91.134
2008	90.975
2009	90.765
2010	90.899
2011	91.647
2012	92.181
2013	91.947
2014	92.144
2015	92.42
2016	92.278
2017	92.24
2018	92.212
2019	92.191
2020	92.176
2021	92.165
2022	92.162
2023	92.156
2024	92.132
2025	92.079
2026	91.996
2027	91.881
2028	91.745
2029	91.61
2030	91.49