Year	Percent
1990	57.888
1991	57.85
1992	57.263
1993	57.068
1994	56.891
1995	56.811
1996	56.766
1997	57.096
1998	57.692
1999	58.207
2000	58.648
2001	58.949
2002	60.125
2003	61.142
2004	61.255
2005	60.931
2006	61.198
2007	61.89
2008	61.986
2009	61.875
2010	61.858
2011	61.601
2012	61.614
2013	61.684
2014	61.087
2015	60.772
2016	60.807
2017	60.689
2018	60.559
2019	60.409
2020	60.233
2021	60.055
2022	59.863
2023	59.665
2024	59.474
2025	59.296
2026	59.166
2027	59.056
2028	58.969
2029	58.907
2030	58.869