Year	Percent
1990	88.252
1991	88.372
1992	88.431
1993	88.568
1994	88.321
1995	88.208
1996	88.22
1997	88.067
1998	87.907
1999	87.712
2000	87.462
2001	87.148
2002	86.791
2003	86.408
2004	86.036
2005	85.686
2006	85.348
2007	85.017
2008	84.633
2009	84.223
2010	83.786
2011	83.361
2012	82.929
2013	82.799
2014	82.628
2015	82.402
2016	82.261
2017	82.125
2018	81.993
2019	81.881
2020	81.797
2021	81.739
2022	81.707
2023	81.69
2024	81.667
2025	81.626
2026	81.577
2027	81.509
2028	81.431
2029	81.354
2030	81.285