Year	% of total
1960	65.48672566371681
1961	59.70149253731344
1962	52.65957446808511
1963	55.440414507772026
1964	56.76855895196506
1965	53.81818181818182
1966	52.68456375838926
1967	43.42857142857143
1968	40.7185628742515
1969	56.03112840466926
1970	40.131578947368425
1971	39.458413926499034
1972	40.909090909090914
1973	42.95302013422819
1974	40.15296367112811
1975	41.206896551724135
1976	44.464944649446494
1977	40.79754601226994
1978	43.293718166383705
1979	52.04582651391162
1980	52.49999999999999
1981	51.20147874306839
1982	47.29493891797557
1983	48.401162790697676
1984	40.0259067357513
1985	44.09613375130617
1986	36.28938156359393
1987	64.55399061032864
1988	63.55498721227622
1989	67.23910171730515
1990	62.56199324324324
1991	62.767262773722635
1992	64.8776923076923
1993	65.79029411764706
1994	66.006
1995	66.00600000000001
1996	66.19245762711866
1997	66.006
1998	65.6567619047619
1999	60.37134146341464
2000	64.76779220779221
2001	60.663950617283945
2002	40.00363636363636
2003	45.90540740740741
2004	49.65053097345133
2005	52.545426829268294
2006	58.59639175257732
2007	50.80970338983051
2008	64.06808656036446
2009	82.44638333333334
2010	67.7147289504037
2011	62.06382544861337
2012	64.70763636363637
2013	56.233078730904815
2014	48.3142509603073
2015	59.34206508135168
2016	47.04081190798376