Year	% of total
1960	0.10586708558158596
1961	0.1705955334987593
1962	0.22621875353466803
1963	0.3816897214477139
1964	0.773589554077359
1965	0.6326222993650938
1966	0.5976137683454756
1967	0.7301692665117823
1968	0.8328676245245263
1969	0.8122623257055173
1970	2.187310803048885
1971	2.3023713993988815
1972	2.303899007166809
1973	2.3370834723745055
1974	2.3578135442802206
1975	2.3216647379732187
1976	2.099413399197283
1977	2.514574248336011
1978	2.967312653642689
1979	3.1930010786009
1980	2.8873582986745605
1981	2.466507197995251
1982	1.9323505688936176
1983	1.763270827126996
1984	1.4542936288088644
1985	1.2383718358862468
1986	1.1748685335148996
1987	1.1837784702905068
1988	1.145385000105663
1989	1.1798854304035056
1990	1.168024402038463
1991	1.151226568621542
1992	1.1148775318126516
1993	1.1929063052534927
1994	1.2648731375755848
1995	1.111338129916376
1996	1.255010836154511
1997	1.3488487600666974
1998	1.3511305595612733
1999	1.3507046378240157
2000	1.338231801863467
2001	1.66851051690428
2002	1.6673801219657682
2003	1.6372350992273794
2004	1.910193379219928
2005	1.7745994760522403
2006	1.808862680699659
2007	1.7598780556937785
2008	1.7620063344321635
2009	1.8018673777966
2010	1.8409945954204303
2011	1.5038193209823563
2012	1.2646016659349084
2013	1.0864396239528844
2014	1.0056274762157116
2015	1.2887836875764418