Year	% of total
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	1.058823529411765
1969	0.9183673469387756
1970	0.7705479452054795
1971	0.78125
1972	0.8778930566640064
1973	1.254355400696864
1974	1.0836845273931366
1975	0.9960159362549801
1976	0.9041591320072333
1977	1.2738853503184715
1978	0.9145269081955679
1979	0.6931886678722121
1980	0.5455537370430987
1981	0.7908611599297013
1982	0.8935361216730038
1983	1.0313144571535722
1984	0.9142659996549941
1985	0.9624457444800906
1986	1.2481997119539128
1987	0.6307617661329452
1988	1.1040339702760085
1989	1.7912068029672517
1990	3.2673910256410252
1991	3.7214603960396038
1992	2.7060371876815803
1993	3.317112763320942
1994	2.8423018203170876
1995	2.3544438827098078
1996	2.201178301467319
1997	1.915248407643312
1998	1.9762275449101796
1999	2.088349420849421
2000	2.2135844642021523
2001	2.051140051238258
2002	2.0208139041966935
2003	3.887387312186978
2004	4.471951219512195
2005	3.2955727440147333
2006	2.620185503263483
2007	3.012444219066937
2008	2.5673844121532365
2009	4.149827320382362
2010	4.201440115440115
2011	6.776202816901408
2012	7.197851487851488
2013	7.058719249302562
2014	7.9570339805825245
2015	7.042224950884086
2016	7.689325813893874