Year	Percent
1980	0.018
1981	0.018
1982	0.018
1983	0.018
1984	0.017
1985	0.018
1986	0.019
1987	0.019
1988	0.019
1989	0.018
1990	0.018
1991	0.019
1992	0.017
1993	0.017
1994	0.017
1995	0.017
1996	0.018
1997	0.019
1998	0.02
1999	0.02
2000	0.02
2001	0.021
2002	0.021
2003	0.022
2004	0.022
2005	0.022
2006	0.022
2007	0.022
2008	0.023
2009	0.024
2010	0.024
2011	0.025
2012	0.026
2013	0.026
2014	0.027
2015	0.027
2016	0.027
2017	0.028
2018	0.029
2019	0.029
2020	0.03
2021	0.031
2022	0.032
2023	0.032
2024	0.033