Year	Percent
1990	61.005
1991	61.147
1992	61.299
1993	61.452
1994	61.595
1995	61.718
1996	61.803
1997	61.867
1998	61.914
1999	61.951
2000	61.983
2001	62.032
2002	62.07
2003	62.09
2004	62.238
2005	61.907
2006	61.554
2007	61.145
2008	60.727
2009	60.552
2010	60.204
2011	59.78
2012	59.346
2013	58.935
2014	58.607
2015	58.379
2016	58.152
2017	58.103
2018	58.095
2019	58.108
2020	58.131
2021	58.162
2022	58.197
2023	58.24
2024	58.293
2025	58.358
2026	58.428
2027	58.508
2028	58.57
2029	58.573
2030	58.493