Year	Percent
1990	59.903
1991	60.059
1992	59.935
1993	59.492
1994	59.455
1995	59.511
1996	59.164
1997	59.176
1998	59.481
1999	59.468
2000	59.467
2001	59.719
2002	59.949
2003	59.977
2004	60.042
2005	60.141
2006	60.099
2007	60.128
2008	59.984
2009	59.582
2010	59.354
2011	58.96
2012	58.552
2013	58.134
2014	57.777
2015	57.499
2016	57.303
2017	57.132
2018	56.979
2019	56.791
2020	56.541
2021	56.305
2022	56.029
2023	55.714
2024	55.403
2025	55.107
2026	54.897
2027	54.714
2028	54.542
2029	54.389
2030	54.241