Year	% of total
1960	4.682779456193353
1961	4.122137404580152
1962	4.4692737430167595
1963	3.979460847240052
1964	3.242542153047989
1965	5.943536404160476
1966	4.781420765027322
1967	4.884667571234735
1968	3.901170351105332
1969	2.693208430913349
1970	7.13436385255648
1971	5.870646766169155
1972	2.7462121212121215
1973	4.770813844714686
1974	3.5555555555555554
1975	2.4318349299926307
1976	3.65950676213206
1977	3.335750543872371
1978	2.617079889807162
1979	0.8733624454148471
1980	0.7692307692307693
1981	3.651685393258427
1982	1.875
1983	5.271439811172305
1984	7.300509337860782
1985	6.1284046692607
1986	5.462555066079296
1987	4.748405386250886
1988	6.278713629402757
1989	6.779661016949152
1990	6.569543973941368
1991	5.976774193548387
1992	7.087478991596638
1993	6.007372013651876
1994	4.997614991482113
1995	5.8142386185243335
1996	5.050674318507891
1997	3.700135542168675
1998	2.7656145251396644
1999	2.594806408544726
2000	2.1387120291616037
2001	2.3129566360052563
2002	3.5582749326145553
2003	3.7624655436447165
2004	3.8496096904441455
2005	4.005966386554622
2006	4.771043010752688
2007	4.2657737459978655
2008	4.144339051463168
2009	3.1315115286080273
2010	4.960893987341772
2011	7.795541059094398
2012	7.49724649629019
2013	7.125943262411348
2014	8.295276114437792
2015	7.745974253949678
2016	6.954992008524242