Year	Percent (Units)
1980	0.014
1981	0.014
1982	0.014
1983	0.014
1984	0.013
1985	0.013
1986	0.013
1987	0.013
1988	0.014
1989	0.014
1990	0.014
1991	0.015
1992	0.014
1993	0.015
1994	0.015
1995	0.015
1996	0.015
1997	0.016
1998	0.016
1999	0.016
2000	0.015
2001	0.014
2002	0.014
2003	0.014
2004	0.014
2005	0.013
2006	0.013
2007	0.013
2008	0.013
2009	0.013
2010	0.013
2011	0.013
2012	0.013
2013	0.013
2014	0.014
2015	0.015
2016	0.016
2017	0.017
2018	0.017
2019	0.018
2020	0.017
2021	0.018
2022	0.019
2023	0.019
2024	0.020
2025	0.020
2026	0.020
2027	0.020
2028	0.020
2029	0.020