Year	Percent
1990	91.715
1991	91.746
1992	91.481
1993	91.195
1994	90.9
1995	90.59
1996	90.289
1997	89.983
1998	89.667
1999	89.347
2000	89.03
2001	88.727
2002	88.424
2003	88.108
2004	87.786
2005	87.445
2006	87.115
2007	86.083
2008	84.974
2009	83.782
2010	82.504
2011	81.153
2012	79.707
2013	78.159
2014	76.504
2015	76.375
2016	76.249
2017	76.12
2018	75.984
2019	75.842
2020	75.695
2021	75.561
2022	75.423
2023	75.285
2024	75.153
2025	75.03
2026	74.927
2027	74.832
2028	74.744
2029	74.661
2030	74.582