Year	Percent
1961	24.84615
1962	24.84615
1963	24.91608
1964	24.84615
1965	24.84615
1966	24.84615
1967	24.94406
1968	24.94406
1969	24.94406
1970	25.88811
1971	25.88811
1972	26.72727
1973	27.64336
1974	27.93007
1975	28.03497
1976	28.14685
1977	28.25175
1978	28.35664
1979	28.46154
1980	28.56643
1981	28.69231
1982	28.71748
1983	28.74266
1984	28.76783
1985	28.78601
1986	28.8951
1987	28.91329
1988	28.93846
1989	28.95664
1990	28.98182
1991	29
1992	29.07832
1993	29.15664
1994	29.23497
1995	29.31329
1996	29.39161
1997	29.46993
1998	29.54825
1999	29.62657
2000	29.64144
2001	29.7105
2002	29.58493
2003	29.48727
2004	29.42449
2005	29.31287
2006	29.19428
2007	29.06174
2008	28.96407
2009	28.88036
2010	28.7827
2011	28.78689
2012	28.74782
2013	28.74782
2014	28.74782
2015	28.74782
2016	28.74782
2017	28.74782
2018	28.74782
2019	28.74782
2020	28.74782
2021	28.74782
