Year	Percent
1990	87.883
1991	87.698
1992	87.534
1993	87.463
1994	87.427
1995	87.4
1996	87.506
1997	87.549
1998	87.834
1999	88.041
2000	88.181
2001	88.252
2002	88.27
2003	88.236
2004	87.968
2005	87.651
2006	87.285
2007	86.865
2008	86.389
2009	85.86
2010	85.275
2011	84.636
2012	83.933
2013	83.891
2014	83.836
2015	83.767
2016	83.702
2017	83.48
2018	83.262
2019	83.047
2020	82.838
2021	82.633
2022	82.432
2023	82.233
2024	82.037
2025	81.843
2026	81.651
2027	81.46
2028	81.27
2029	81.081
2030	80.893