Year	Percent
1990	58.56
1991	58.623
1992	58.665
1993	58.712
1994	58.609
1995	58.523
1996	58.4
1997	58.242
1998	58.022
1999	57.865
2000	57.638
2001	57.347
2002	57.023
2003	56.731
2004	56.425
2005	56.119
2006	55.819
2007	55.504
2008	55.248
2009	55.076
2010	54.82
2011	54.541
2012	54.276
2013	54.028
2014	53.766
2015	53.493
2016	53.261
2017	53.022
2018	52.782
2019	52.546
2020	52.312
2021	52.107
2022	51.904
2023	51.706
2024	51.498
2025	51.277
2026	51.069
2027	50.853
2028	50.63
2029	50.407
2030	50.188