Year	% of total
1960	1.5253476895468818
1961	1.4425116673737801
1962	1.250459727841118
1963	1.361519168756718
1964	5.381165919282511
1965	5.209929512718357
1966	4.923928077455049
1967	4.403866809881848
1968	4.753476611883691
1969	4.624970045530794
1970	4.082474226804124
1971	3.881008668242711
1972	3.87409200968523
1973	3.526354862657758
1974	3.3991416309012874
1975	4.273789649415692
1976	4.640522875816994
1977	4.100549882168107
1978	4.440816326530612
1979	4.148831083305893
1980	4.256612952265126
1981	5.005324813631523
1982	5.484120836560805
1983	4.626143087681549
1984	5.617579301789828
1985	6.089080999812065
1986	6.143001007049346
1987	4.892618404209928
1988	4.790419161676647
1989	4.9361987911349905
1990	6.34570528356762
1991	5.997169620253165
1992	6.132344127597873
1993	6.196787372330547
1994	6.231932021466905
1995	3.7247480314960635
1996	3.6881506849315064
1997	2.8207692307692307
1998	4.101974474474475
1999	5.136851595006935
2000	4.914270137179036
2001	3.9786115326251896
2002	4.166137931034482
2003	4.709658500371195
2004	6.338169329073483
2005	10.679333333333334
2006	12.329520592020591
2007	15.684998534154207
2008	19.285985477178425
2009	22.54043666026871
2010	27.625216150976517
2011	24.034022231370933
2012	26.78418647922266
2013	23.97767770597738
2014	31.330248059079725
2015	30.21084726867335
2016	30.254533875818147