Year	Percent
1990	57.959
1991	60.076
1992	60.426
1993	59.777
1994	59.181
1995	58.311
1996	57.811
1997	58.468
1998	57.965
1999	57.23
2000	56.831
2001	56.322
2002	56.019
2003	55.258
2004	54.525
2005	53.836
2006	53.376
2007	53.012
2008	52.718
2009	51.518
2010	52.682
2011	54.173
2012	55.701
2013	51.411
2014	51.931
2015	55.665
2016	55.607
2017	55.618
2018	55.725
2019	55.903
2020	56.135
2021	56.463
2022	56.861
2023	57.289
2024	57.683
2025	58.004
2026	58.288
2027	58.488
2028	58.617
2029	58.705
2030	58.772