Year	Percent
1990	42.234
1991	47.784
1992	47.422
1993	47.147
1994	48.13
1995	49.006
1996	51.261
1997	51.392
1998	51.474
1999	51.354
2000	50.965
2001	51.663
2002	52.453
2003	54.721
2004	56.981
2005	59.215
2006	59.408
2007	58.2
2008	59.062
2009	57.576
2010	58.555
2011	59.098
2012	59.574
2013	59.979
2014	60.117
2015	58.844
2016	58.339
2017	58.567
2018	58.747
2019	58.883
2020	58.982
2021	59.076
2022	59.134
2023	59.182
2024	59.262
2025	59.401
2026	59.619
2027	59.902
2028	60.221
2029	60.536
2030	60.822