Year	% of total
1960	0
1961	0.002812069401872838
1962	0.007667927614763315
1963	0.0071396273114543414
1964	0.014604936468526362
1965	0.17012438965113452
1966	0.18146495591469014
1967	0.2831594634873324
1968	0.4012762542329751
1969	0.5229662955913172
1970	0.473541791942273
1971	0.5272439037423631
1972	0.5537974683544303
1973	0.521420748949803
1974	0.586422192365447
1975	0.6877399092706759
1976	0.870230068812122
1977	0.889642303345686
1978	0.9688993665885157
1979	1.0214542445314527
1980	0.7929186178225683
1981	0.85171316638168
1982	1.248072828720358
1983	1.3857685156492099
1984	1.5910658440490926
1985	1.688797215418332
1986	2.2551510245950905
1987	2.617671345995045
1988	2.8845886507075926
1989	3.2008207882353688
1990	3.753837647560802
1991	3.882911878025488
1992	4.328184082759496
1993	4.140949928732355
1994	4.218955592702958
1995	5.273631898529213
1996	5.1214872798434445
1997	5.607097799094317
1998	5.671901456247098
1999	4.684288400491101
2000	4.670289203016476
2001	4.571256028011909
2002	4.7767954391259
2003	4.924635639685399
2004	4.56456654310654
2005	4.436859212122277
2006	4.0751491043854235
2007	3.9472190704288606
2008	4.431417605416187
2009	5.817291412979031
2010	6.023990668404081
2011	5.193320024988641
2012	4.094746537983935
2013	5.180161174694048
2014	4.337859860450098
2015	4.603916436457665
2016	4.389254287127624