Year	Percent
1990	89.671
1991	89.021
1992	88.822
1993	88.846
1994	89.033
1995	89.267
1996	88.672
1997	88.203
1998	87.966
1999	87.977
2000	88.151
2001	87.267
2002	86.679
2003	86.6
2004	86.875
2005	87.303
2006	86.92
2007	86.937
2008	87.263
2009	87.769
2010	88.297
2011	87.596
2012	87.862
2013	88.052
2014	88.177
2015	88.143
2016	88.095
2017	88.09
2018	88.197
2019	88.415
2020	88.735
2021	88.09
2022	87.716
2023	87.565
2024	87.572
2025	87.649
2026	87.05
2027	86.562
2028	86.225
2029	86.069
2030	86.054