Year	Percent (Units)
1980	0.003
1981	0.003
1982	0.003
1983	0.003
1984	0.003
1985	0.003
1986	0.003
1987	0.003
1988	0.003
1989	0.003
1990	0.003
1991	0.003
1992	0.003
1993	0.003
1994	0.003
1995	0.003
1996	0.003
1997	0.003
1998	0.002
1999	0.003
2000	0.002
2001	0.003
2002	0.003
2003	0.002
2004	0.002
2005	0.002
2006	0.002
2007	0.002
2008	0.002
2009	0.002
2010	0.002
2011	0.002
2012	0.002
2013	0.002
2014	0.002
2015	0.003
2016	0.003
2017	0.003
2018	0.003
2019	0.003
2020	0.003
2021	0.003
2022	0.003
2023	0.003
2024	0.003
2025	0.004
2026	0.004
2027	0.004
2028	0.004
2029	0.004