Year	Percent
1961	9.38895
1962	9.59047
1963	9.97069
1964	10.15985
1965	10.64477
1966	10.67761
1967	10.87104
1968	11.26252
1969	11.43187
1970	11.82471
1971	12.04925
1972	12.41829
1973	12.6644
1974	12.84879
1975	13.25259
1976	13.51277
1977	13.91186
1978	14.39659
1979	14.72869
1980	14.96576
1981	15.35471
1982	15.54646
1983	15.84368
1984	15.87618
1985	16.48379
1986	17.40953
1987	18.48547
1988	19.43022
1989	20.45868
1990	20.56491
1991	20.68026
1992	20.71679
1993	20.97519
1994	21.27804
1995	21.20225
1996	21.18734
1997	21.18003
1998	21.13742
1999	21.14473
2000	21.11916
2001	21.14442
2002	21.41988
2003	21.65953
2004	21.70659
2005	21.71484
2006	21.53462
2007	21.63202
2008	21.76351
2009	21.97535
2010	22.49064
2011	22.92071
2012	23.82955
2013	24.5299
2014	24.6203
2015	26.08422
2016	26.08735
2017	26.08735
2018	26.08735
2019	26.08735
2020	26.08735
2021	26.08735