Year	Percent (Units)
1980	0.010
1981	0.011
1982	0.010
1983	0.010
1984	0.010
1985	0.011
1986	0.011
1987	0.011
1988	0.011
1989	0.011
1990	0.011
1991	0.011
1992	0.010
1993	0.009
1994	0.009
1995	0.008
1996	0.007
1997	0.007
1998	0.007
1999	0.007
2000	0.006
2001	0.006
2002	0.006
2003	0.006
2004	0.006
2005	0.006
2006	0.006
2007	0.006
2008	0.006
2009	0.006
2010	0.006
2011	0.006
2012	0.006
2013	0.007
2014	0.007
2015	0.008
2016	0.007
2017	0.007
2018	0.007
2019	0.007
2020	0.007
2021	0.007
2022	0.007
2023	0.007
2024	0.007
2025	0.007
2026	0.007
2027	0.007
2028	0.007
2029	0.007