Year	% of total
1960	3.537663921927417
1961	4.036243822075782
1962	7.308884297520661
1963	5.614358030372756
1964	11.242480813109314
1965	10.334476843910807
1966	1.8813832646479127
1967	4.591321897073663
1968	13.288504642971501
1969	3.865227537922987
1970	19.46759881688626
1971	20.04812563323202
1972	18.563348416289593
1973	23.1515522875817
1974	25.053813757604114
1975	37.89365479861695
1976	50.05972526378658
1977	25.952813067150636
1978	24.35783272826906
1979	28.817871548246977
1980	45.18611074575825
1981	61.44386574074075
1982	52.63397799049293
1983	53.29862072785687
1984	47.184162542328735
1985	40.239234449760765
1986	55.13356619274856
1987	51.415211659951254
1988	42.524531668153436
1989	74.62914399780813
1990	65.28473643356149
1991	66.87634553283101
1992	81.42996995577761
1993	69.54501452081317
1994	62.85504563732687
1995	71.69925174993965
1996	54.1389429642328
1997	58.32063752490332
1998	63.6389338679415
1999	79.72689565176866
2000	69.7385409941898
2001	65.35262519494022
2002	78.10733844468784
2003	61.34863824939275
2004	71.93209449662034
2005	81.45622239542737
2006	67.00428194993412
2007	64.8072330262709
2008	67.16437603078614
2009	62.43280384786387
2010	46.57763871039839
2011	52.89855072463768
2012	56.93127962085308
2013	41.08916768908062
2014	38.76710483265652
2015	51.87301339677464