Year	% of total
1960	0
1961	0
1962	0.3516998827667057
1963	0.42238648363252373
1964	17.585848074921955
1965	46.82884448305821
1966	33.9622641509434
1967	8.553766532489938
1968	10.82272899080257
1969	9.494131089643709
1970	0
1971	0.006131207847946045
1972	0.7715164468539852
1973	0.9944495837187789
1974	1.0504825538233111
1975	1.2672709671741618
1976	1.0977503340194272
1977	0.9836472523039689
1978	1.00965060356085
1979	0.8919564640297318
1980	12.964045284325824
1981	24.322460664061683
1982	10.87632213768788
1983	5.225528814408342
1984	22.433119819140916
1985	22.6578595246692
1986	23.611533711585615
1987	26.97765642425874
1988	27.5775295544653
1989	27.793376529877612
1990	54.62483442514574
1991	59.79680081453298
1992	56.99071682969652
1993	58.105438630522286
1994	56.9600964395082
1995	34.15388399280575
1996	33.86911316160451
1997	38.40684734564742
1998	36.44400546851265
1999	35.16429881038673
2000	36.11921461897356
2001	32.71093805309735
2002	35.598380352927954
2003	35.23146956240337
2004	40.56371809251895
2005	41.220369938829016
2006	41.1483523679001
2007	32.67938221160763
2008	32.76834423398912
2009	29.950424142331656
2010	31.234160690298935
2011	30.597813519609346
2012	31.04063918158568
2013	30.702992510713283
2014	29.66744471973324
2015	35.759686887407774
2016	38.254067069008876