Year	% of total
1960	0
1961	7.4365175332527205
1962	12.160413971539457
1963	11.14864864864865
1964	21.090201168072685
1965	26.959421901056142
1966	21.966072205306652
1967	21.242397914856646
1968	20.801295022258195
1969	21.98373983739837
1970	0.9000243249817562
1971	3.6142211746218815
1972	11.072306299314448
1973	8.22166921898928
1974	7.688771405585565
1975	13.932455638236977
1976	15.493353304624602
1977	8.61344537815126
1978	38.18320431620924
1979	17.916566192428263
1980	38.33517089305402
1981	24.060328490208466
1982	18.274348678681484
1983	31.586649014005992
1984	42.944816915936045
1985	38.087561086200814
1986	43.41137445315129
1987	47.72885789014821
1988	46.46398462412091
1989	45.85184845847267
1990	57.357302990131096
1991	57.453683896026284
1992	48.3039676541717
1993	49.17283789301756
1994	52.29639133473095
1995	64.69581930184806
1996	70.87
1997	53.60274886722504
1998	73.3645975315267
1999	65.72603301521795
2000	50.56997836874921
2001	54.91917346529357
2002	55.57732744683497
2003	52.55566793893129
2004	48.58375427023207
2005	68.84020901224856
2006	52.63660693333334
2007	50.853541583764425
2008	49.61152322338687
2009	48.71773876030859
2010	47.20687201697013
2011	48.05216438124259
2012	50.670272425773845
2013	50.422308521283966
2014	53.23371298897774
2015	54.00641638692883
2016	54.929536798046726