Year	% of total
1960	0.8830132202544275
1961	1.1597004107272288
1962	1.1569593524546893
1963	1.225982796044698
1964	1.589945487583283
1965	3.0029920455374737
1966	5.522340538437046
1967	9.680631868131869
1968	15.01324032810179
1969	15.976462399949382
1970	24.923784426187154
1971	32.51164848895021
1972	37.51713880690665
1973	39.42929248206854
1974	43.69657631302281
1975	47.02485082316854
1976	44.21152724050743
1977	45.14386481841113
1978	45.79758756369735
1979	45.029970517601576
1980	44.609250728200465
1981	49.44202383069536
1982	46.704886704886704
1983	48.279977720605785
1984	48.661425285031726
1985	50.101620978535664
1986	46.19894864536999
1987	45.40931596404364
1988	42.7366214057508
1989	47.13566257475606
1990	47.43988136164476
1991	50.95389913899139
1992	49.74592000521989
1993	49.58918367346939
1994	48.5361529665862
1995	48.07219666544968
1996	50.03962224011039
1997	49.18335115329169
1998	48.74834052240594
1999	48.99768992823558
2000	49.401697473813925
2001	49.07953106332138
2002	48.94952417910447
2003	48.34691892526106
2004	48.89191333643122
2005	48.1663517294755
2006	47.90776128519944
2007	46.377092267508964
2008	47.993156780942016
2009	50.63539055687056
2010	53.61455655526992
2011	50.519058979039464
2012	48.68924898425596
2013	48.65916687881873
2014	44.469316832343715
2015	41.46625324141421
2016	43.45396158463386