Year	Percent
1961	3.46339
1962	3.46339
1963	3.50723
1964	3.50723
1965	3.50723
1966	3.55107
1967	3.55107
1968	3.55107
1969	3.59491
1970	3.59491
1971	3.63875
1972	3.63875
1973	3.6826
1974	3.6826
1975	3.72644
1976	3.72644
1977	3.77028
1978	4.07716
1979	4.121
1980	4.20868
1981	4.25252
1982	4.25252
1983	4.25252
1984	4.25252
1985	4.42788
1986	4.51556
1987	4.91013
1988	5.04165
1989	5.26085
1990	5.52389
1991	5.69925
1992	5.9623
1993	6.26918
1994	6.26918
1995	6.4007
1996	6.44454
1997	6.48838
1998	6.48838
1999	6.57606
2000	6.53222
2001	6.53222
2002	6.66374
2003	6.66374
2004	6.66374
2005	6.66374
2006	6.66374
2007	6.66374
2008	6.66374
2009	6.79527
2010	6.88295
2011	6.88295
2012	7.01447
2013	7.01447
2014	7.01447
2015	7.45287
2016	7.45287
2017	7.54055
2018	7.54055
2019	7.62823
2020	7.89128
2021	7.97896