Year	% of total
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0.2691790040376851
1966	0.3834874802616738
1967	1.030311087476735
1968	1.47230949300807
1969	1.3700900502734656
1970	1.347305389221557
1971	0.8839463929284289
1972	0.5763369354391799
1973	0.5594331077841121
1974	1.1784078629136008
1975	3.0465769925717727
1976	5.326245047394554
1977	6.5405222763913695
1978	6.508715823611549
1979	7.162381283298585
1980	9.360654961904311
1981	9.831127339114559
1982	9.715610887342855
1983	10.189506147790448
1984	10.644281217208816
1985	10.004914407404373
1986	10.316506410256409
1987	11.777181960062427
1988	14.060662073601076
1989	12.71666525746174
1990	15.119645187601957
1991	16.235906841835863
1992	15.198793760203156
1993	14.069897610921503
1994	14.415859491778777
1995	17.272247211556042
1996	19.453881220486743
1997	15.878652801199175
1998	14.163506621862028
1999	13.889900677200902
2000	15.495677359796908
2001	13.586481160675618
2002	12.623960577584231
2003	11.96043850490708
2004	12.1015663416702
2005	13.41043650793651
2006	13.568723708392893
2007	13.101406309388066
2008	13.339876074355386
2009	11.52071212473819
2010	11.74911705685619
2011	12.129818804107108
2012	12.442768173758864
2013	13.794992466097439
2014	12.816699029126214
2015	13.300977847393153
2016	14.741796837565882