Year	% of total
1960	11.180444240897641
1961	4.951781861662031
1962	4.024852100299512
1963	6.763511018096763
1964	5.057121432667285
1965	5.396211040945203
1966	10.054519595448799
1967	8.334881646910187
1968	13.250311332503115
1969	27.851262443594777
1970	31.22483332233151
1971	21.450686866865063
1972	22.635479323964105
1973	20.084550345887777
1974	20.548528824390893
1975	13.190237362200815
1976	17.60926937679415
1977	18.025536454455544
1978	11.922397829550837
1979	13.253949887446618
1980	10.570414053739773
1981	4.336580907376077
1982	4.38138113996302
1983	2.6095582764607004
1984	2.0621734756790087
1985	3.767421762280374
1986	3.7412010080820366
1987	3.2299608842488885
1988	2.9023420602714896
1989	2.2740630860085647
1990	2.2118862341078476
1991	3.3653126488398994
1992	4.000383729854183
1993	4.632797923537147
1994	5.60406447091801
1995	5.095318052773901
1996	8.60929977884759
1997	4.748468560245566
1998	4.2748014685970865
1999	4.314186440021183
2000	3.0716582547803157
2001	3.632538135462112
2002	4.838445807770961
2003	6.452994925357699
2004	2.9827325891885836
2005	2.1273640008840338
2006	2.643663721508033
2007	2.184474174018801
2008	2.064792453333689
2009	2.319112178267108
2010	4.4308231173380035
2011	2.5290508072996394
2012	1.5255113076497873
2013	1.544785043553267
2014	1.0393737707907316
2015	1.0850300436605715