Year	Percent
1961	27.47568
1962	27.22054
1963	32.84963
1964	33.53532
1965	34.38048
1966	35.16186
1967	35.95918
1968	37.01164
1969	37.12327
1970	37.203
1971	37.29868
1972	37.39435
1973	37.49003
1974	37.58571
1975	37.6176
1976	38.20762
1977	38.79764
1978	39.37171
1979	37.6176
1980	37.45814
1981	37.45814
1982	36.61298
1983	36.80434
1984	36.85218
1985	36.91596
1986	37.09137
1987	37.21894
1988	37.26678
1989	37.31462
1990	37.29868
1991	37.34652
1992	37.37841
1993	36.99569
1994	37.04353
1995	37.09137
1996	37.10732
1997	37.12327
1998	37.13921
1999	37.39435
2000	37.47409
2001	37.49003
2002	37.56977
2003	37.79302
2004	36.83623
2005	40.02551
2006	38.90926
2007	38.11194
2008	41.38096
2009	41.62016
2010	41.77962
2011	43.53373
2012	43.69319
2013	43.69319
2014	43.69319
2015	44.26995
2016	44.43152
2017	44.59632
2018	45.44808
2019	45.44729
2020	45.45748
2021	45.45748