Year	Percent
1961	7.60538
1962	7.62143
1963	7.63427
1964	7.65675
1965	7.6728
1966	7.68885
1967	7.7049
1968	7.72095
1969	7.73701
1970	7.75306
1971	7.76911
1972	7.78516
1973	7.80121
1974	7.81727
1975	7.84937
1976	7.86542
1977	7.88147
1978	7.89752
1979	7.91358
1980	7.93765
1981	7.93765
1982	7.94568
1983	7.94568
1984	7.94889
1985	7.9505
1986	7.9521
1987	7.95371
1988	7.95531
1989	7.95531
1990	7.95531
1991	7.95852
1992	7.96173
1993	7.96173
1994	7.96173
1995	7.94568
1996	7.94568
1997	7.94568
1998	7.94568
1999	7.94568
2000	7.94889
2001	7.94889
2002	7.94889
2003	7.93765
2004	7.93765
2005	7.93765
2006	7.92963
2007	7.92963
2008	7.92963
2009	7.92321
2010	7.87666
2011	7.82529
2012	7.83332
2013	7.84295
2014	7.87666
2015	7.87666
2016	7.87666
2017	7.87666
2018	7.87987
2019	7.87987
2020	7.87987
2021	7.88147