Year	Percent
1990	58.915
1991	58.873
1992	58.797
1993	58.681
1994	58.631
1995	58.585
1996	58.61
1997	58.564
1998	58.526
1999	58.452
2000	58.353
2001	58.352
2002	58.379
2003	58.419
2004	58.46
2005	58.489
2006	58.568
2007	58.632
2008	58.681
2009	58.696
2010	58.74
2011	58.824
2012	58.892
2013	58.954
2014	58.999
2015	59.009
2016	59.002
2017	59.044
2018	59.087
2019	59.129
2020	59.172
2021	59.215
2022	59.257
2023	59.3
2024	59.342
2025	59.385
2026	59.428
2027	59.47
2028	59.513
2029	59.555
2030	59.598