Year	Percent
1961	6.5098
1962	6.56801
1963	6.62623
1964	6.68444
1965	6.74266
1966	6.80087
1967	6.85908
1968	6.9173
1969	6.97551
1970	7.03373
1971	7.11134
1972	7.16956
1973	7.24718
1974	7.30539
1975	7.37913
1976	7.51496
1977	7.60422
1978	7.6896
1979	7.69736
1980	7.70513
1981	7.71289
1982	7.72065
1983	7.72841
1984	7.73617
1985	7.74394
1986	7.7517
1987	7.75946
1988	7.76722
1989	7.77498
1990	7.78275
1991	7.80666
1992	7.83057
1993	7.85449
1994	7.8784
1995	7.90232
1996	7.92623
1997	7.95015
1998	7.97406
1999	7.99797
2000	8.02189
2001	8.04152
2002	8.06116
2003	8.08079
2004	8.10042
2005	8.12006
2006	8.13969
2007	8.15932
2008	8.17896
2009	8.19859
2010	8.21822
2011	8.26434
2012	8.31045
2013	8.35656
2014	8.35656
2015	8.35656
2016	8.35656
2017	8.35656
2018	8.35656
2019	8.35656
2020	8.35656
2021	8.35656