Year	Percent
1990	82.477
1991	82.483
1992	82.414
1993	82.36
1994	82.267
1995	82.134
1996	81.991
1997	81.872
1998	81.824
1999	81.809
2000	81.728
2001	81.684
2002	81.64
2003	81.58
2004	81.5
2005	81.417
2006	81.338
2007	81.244
2008	81.21
2009	81.222
2010	81.609
2011	82.016
2012	82.476
2013	82.948
2014	83.475
2015	83.904
2016	83.48
2017	83.47
2018	83.381
2019	83.228
2020	83.019
2021	82.747
2022	82.419
2023	82.051
2024	81.665
2025	81.279
2026	80.894
2027	80.513
2028	80.144
2029	79.795
2030	79.474