Year	Percent
1990	93.978
1991	94.152
1992	94.162
1993	94.231
1994	94.194
1995	94.233
1996	94.242
1997	94.224
1998	94.205
1999	94.132
2000	94.053
2001	93.99
2002	93.881
2003	93.729
2004	93.545
2005	93.362
2006	93.137
2007	92.89
2008	92.613
2009	92.333
2010	92.068
2011	91.76
2012	91.434
2013	91.106
2014	90.772
2015	90.454
2016	90.208
2017	90.198
2018	90.209
2019	90.22
2020	90.218
2021	90.208
2022	90.189
2023	90.157
2024	90.107
2025	90.035
2026	89.943
2027	89.827
2028	89.702
2029	89.591
2030	89.506