Year	% of total
1960	55.113024757804084
1961	59.71479500891266
1962	55.96491228070175
1963	45.92186429061
1964	44.45564516129032
1965	36.19077306733167
1966	40.11363636363636
1967	51.670951156812336
1968	53.17855168601437
1969	30.971843778383285
1970	25.51923731699012
1971	19.856866977166877
1972	16.995662565282817
1973	17.32248520710059
1974	15.51774886678048
1975	20.31721470019342
1976	20.4566573742201
1977	17.476432197244378
1978	18.936977980258163
1979	19.527337228714526
1980	30.95340578930378
1981	37.86623672652472
1982	44.404695360536614
1983	49.177017683411854
1984	54.237109601306166
1985	50.83420776495278
1986	51.908206535295584
1987	45.387134647469566
1988	46.96003731923496
1989	76.81873163988249
1990	43.92293146647015
1991	41.299241762604204
1992	40.66380439814815
1993	39.13754649922995
1994	29.243106916677014
1995	27.293381162619575
1996	29.309080064234916
1997	35.09416447210917
1998	33.416398747390396
1999	36.09043128850791
2000	41.495380570527146
2001	43.72838285378744
2002	43.670984786900476
2003	38.60108818222824
2004	34.832983188536616
2005	40.45843864282811
2006	34.71320607375271
2007	30.270143126594917
2008	36.62993663279799
2009	36.73915140086207
2010	65.47492560343878
2011	68.68486041727887
2012	56.243359157727454
2013	56.237048410404626
2014	57.36551290877796
2015	50.12075265834489
2016	56.87536616860358