Year	Percent
1990	63.894
1991	63.841
1992	63.647
1993	63.657
1994	63.669
1995	63.653
1996	63.648
1997	63.6
1998	63.624
1999	63.636
2000	63.73
2001	63.659
2002	63.834
2003	63.908
2004	65.223
2005	64.44
2006	63.644
2007	62.857
2008	62.073
2009	61.287
2010	60.5
2011	59.697
2012	58.897
2013	58.102
2014	57.316
2015	57.216
2016	57.298
2017	57.144
2018	56.994
2019	56.847
2020	56.701
2021	56.548
2022	56.4
2023	56.261
2024	56.142
2025	56.047
2026	55.963
2027	55.902
2028	55.856
2029	55.815
2030	55.774