Year	Percent
1961	6.89782
1962	6.94656
1963	6.9953
1964	7.04404
1965	7.09278
1966	7.10505
1967	7.09
1968	7.07494
1969	7.05988
1970	7.04482
1971	7.02943
1972	7.03244
1973	7.03545
1974	7.03847
1975	7.04148
1976	7.0446
1977	7.00289
1978	6.96106
1979	6.91923
1980	6.87741
1981	6.83614
1982	6.82744
1983	6.81874
1984	6.81004
1985	6.80134
1986	6.79251
1987	6.80658
1988	6.82063
1989	6.83469
1990	6.84874
1991	6.86327
1992	6.85566
1993	6.84807
1994	6.84049
1995	6.8329
1996	6.82521
1997	6.82777
1998	6.83045
1999	6.83313
2000	6.8358
2001	6.83816
2002	6.92548
2003	6.90931
2004	6.89313
2005	6.87696
2006	6.75739
2007	6.69315
2008	6.6289
2009	6.56465
2010	6.50041
2011	6.43568
2012	6.44364
2013	6.45156
2014	6.45947
2015	6.46751
2016	6.47476
2017	6.45441
2018	6.45682
2019	6.43436
2020	6.37074
2021	6.48458