Year	% of total
1960	2.581087254454088
1961	4.570815450643777
1962	3.8059554328534806
1963	3.2834297380061246
1964	4.755747126436781
1965	3.71451313345715
1966	2.540033130866924
1967	5.646664181885949
1968	5.043227665706052
1969	6.404766337739715
1970	5.66452485627325
1971	3.977724741447892
1972	3.679747017392554
1973	3.7756202804746493
1974	5.909601347557553
1975	11.460912628227803
1976	6.622727755926439
1977	6.711214410226613
1978	5.064826042346796
1979	4.2349726775956285
1980	4.020426359730891
1981	5.682635592001151
1982	5.702608018684313
1983	3.9565803840966014
1984	3.5383996783273015
1985	3.5615966964900205
1986	3.7080751450772103
1987	3.9115729621097004
1988	3.4686346863468636
1989	3.9270473480999795
1990	3.8731156415572445
1991	3.0192549502181447
1992	2.8088504875406284
1993	3.7217075029946636
1994	4.276681707740368
1995	2.670320017415914
1996	3.5468760979642453
1997	2.7442535590611774
1998	2.5572014276562642
1999	2.1873445539373857
2000	2.787777777777778
2001	2.2000239980801535
2002	2.3166345702207605
2003	2.3358823529411765
2004	2.2383888149134488
2005	1.9112516345974222
2006	1.732355584461657
2007	1.6017845579761838
2008	1.5104658417935701
2009	1.3768366668371783
2010	2.101293638676845
2011	0.8439502008828927
2012	0.8493780895438069
2013	0.8085767238511619
2014	0.6905774290330026
2015	0.595613631334366
2016	0.5783565566763549