Year	% of total
1960	3.8185390248258613
1961	7.154107601757439
1962	7.90904443996964
1963	4.851744431616591
1964	4.892465367426377
1965	5.227982662178851
1966	5.6805978163594055
1967	8.568904593639576
1968	6.822916162036992
1969	6.8341057548443604
1970	4.904889438263975
1971	4.736120077469335
1972	3.4736433297981986
1973	3.6000166763945636
1974	4.491903850591093
1975	4.106243740482103
1976	5.024631759826434
1977	5.430473211362893
1978	5.93637902252208
1979	8.381052408114012
1980	9.946913459127723
1981	11.347050079908803
1982	13.256079988560494
1983	13.412988801225925
1984	15.413948206372888
1985	16.474700527335283
1986	16.413351332751
1987	16.659774474008028
1988	16.890228710947234
1989	15.47401202230645
1990	16.778092114831548
1991	14.727922764581205
1992	11.229723175310328
1993	9.190197729186101
1994	10.030602430707352
1995	11.614229622015133
1996	10.577782604700122
1997	10.04729762619461
1998	10.970412568252154
1999	10.886964571560819
2000	11.307656117447888
2001	13.525491551854769
2002	14.581381606445381
2003	15.410544994725406
2004	17.20113463859597
2005	16.648362754345776
2006	16.39241966778359
2007	16.13609670951457
2008	15.498186759035107
2009	15.057485216848457
2010	14.872160469654219
2011	16.67697772810729
2012	18.200593344052095
2013	16.84316919582229
2014	16.72827165643113
2015	16.12007302121735