Year	Percent
1961	69.98597
1962	69.99394
1963	70.00191
1964	70.00988
1965	70.01785
1966	70.02582
1967	70.03379
1968	70.04176
1969	70.04973
1970	70.0577
1971	70.06567
1972	70.07364
1973	70.08161
1974	70.08958
1975	70.09755
1976	70.10552
1977	70.1135
1978	70.12147
1979	70.12944
1980	70.13741
1981	70.14538
1982	70.15335
1983	70.16132
1984	70.16929
1985	70.17726
1986	70.18523
1987	70.1932
1988	70.19957
1989	70.20117
1990	70.20435
1991	70.20435
1992	70.20595
1993	70.20754
1994	70.21711
1995	70.22667
1996	70.23464
1997	70.24261
1998	70.24421
1999	70.24421
2000	70.24421
2001	70.25058
2002	70.28087
2003	70.31116
2004	70.38767
2005	70.33825
2006	70.25855
2007	70.17885
2008	70.33825
2009	70.33825
2010	70.33825
2011	70.17885
2012	70.17885
2013	70.33825
2014	70.33825
2015	70.33825
2016	70.33825
2017	70.33825
2018	70.33825
2019	70.33985
2020	70.34144
2021	70.34304