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