Year	Percent
1990	82.481
1991	82.684
1992	82.787
1993	82.874
1994	82.665
1995	82.508
1996	82.343
1997	82.131
1998	81.814
1999	81.683
2000	81.406
2001	81.136
2002	80.794
2003	80.531
2004	80.22
2005	79.892
2006	79.559
2007	79.174
2008	78.913
2009	78.849
2010	78.594
2011	78.267
2012	77.974
2013	77.71
2014	77.441
2015	77.157
2016	76.956
2017	76.771
2018	76.595
2019	76.42
2020	76.24
2021	76.053
2022	75.867
2023	75.67
2024	75.459
2025	75.224
2026	74.972
2027	74.702
2028	74.42
2029	74.14
2030	73.873