Year	Percent (Units)
1980	0.015
1981	0.015
1982	0.016
1983	0.016
1984	0.016
1985	0.016
1986	0.017
1987	0.018
1988	0.019
1989	0.019
1990	0.019
1991	0.020
1992	0.019
1993	0.019
1994	0.020
1995	0.020
1996	0.020
1997	0.020
1998	0.021
1999	0.021
2000	0.022
2001	0.022
2002	0.021
2003	0.022
2004	0.022
2005	0.021
2006	0.021
2007	0.021
2008	0.021
2009	0.022
2010	0.022
2011	0.022
2012	0.021
2013	0.022
2014	0.022
2015	0.022
2016	0.023
2017	0.023
2018	0.023
2019	0.023
2020	0.020
2021	0.020
2022	0.021
2023	0.021
2024	0.022
2025	0.022
2026	0.022
2027	0.022
2028	0.022
2029	0.022