Year	Percent
1980	0.024
1981	0.024
1982	0.024
1983	0.024
1984	0.023
1985	0.023
1986	0.023
1987	0.023
1988	0.023
1989	0.022
1990	0.02
1991	0.022
1992	0.022
1993	0.026
1994	0.026
1995	0.024
1996	0.025
1997	0.023
1998	0.023
1999	0.023
2000	0.021
2001	0.021
2002	0.02
2003	0.021
2004	0.02
2005	0.019
2006	0.019
2007	0.02
2008	0.019
2009	0.021
2010	0.022
2011	0.021
2012	0.021
2013	0.021
2014	0.024
2015	0.024
2016	0.024
2017	0.024
2018	0.023
2019	0.023
2020	0.023
2021	0.023
2022	0.023
2023	0.023
2024	0.023