Year	% of total
1960	0.06850419084461637
1961	0.07508397549891327
1962	0.0784841349927122
1963	0.06586473463445072
1964	0.07074887686157984
1965	0.09042220212839952
1966	0.19170442662948764
1967	0.8632455302306536
1968	2.0197333828214403
1969	4.010560351220669
1970	6.243979332691129
1971	8.907395673033403
1972	10.401076263348187
1973	11.805867286314067
1974	14.17491525423729
1975	15.28966573565186
1976	15.329723021379815
1977	15.555104878896742
1978	14.367847117253291
1979	15.211024528005856
1980	15.082527034718268
1981	15.176961059696637
1982	13.217082072558256
1983	16.04546274580552
1984	15.96229434067272
1985	16.065286065286067
1986	13.11755899336993
1987	14.651493598862023
1988	14.860963934665838
1989	15.420576693397031
1990	17.11557405543866
1991	17.553075640575642
1992	18.450889343897444
1993	19.56554808827536
1994	19.27967536988686
1995	21.210796019900496
1996	22.65588949351193
1997	22.120209190672153
1998	23.925631856628424
1999	26.44138429573197
2000	26.107989427012278
2001	25.508487409160047
2002	27.642266125394677
2003	28.558151515151515
2004	29.266532187335553
2005	30.523523189585035
2006	31.745791072250345
2007	32.799297255951814
2008	31.783181520620968
2009	34.62071837062305
2010	36.022497417112795
2011	34.51361829025845
2012	34.67740101095199
2013	34.339456577994
2014	32.21640084294587
2015	33.603894957983194
2016	34.72219783715013