Year	% of total
1960	1.366120218579235
1961	3.7303664921465964
1962	3.0821917808219177
1963	0.14760147601476015
1964	5.0471063257065945
1965	6.648757555406314
1966	6.433166547533952
1967	6.89900426742532
1968	6.886858749121575
1969	5.902777777777778
1970	7.0744288872512895
1971	4.126031507876969
1972	4.751461988304094
1973	3.3715925394548063
1974	6.6827697262479875
1975	6.7362428842504745
1976	4.197080291970803
1977	7.130281690140845
1978	6.935908691834943
1979	8.287795992714026
1980	10.675381263616558
1981	14.835164835164836
1982	17.52767527675277
1983	19.574468085106382
1984	17.100371747211895
1985	16.76300578034682
1986	17.006802721088434
1987	19.20415224913495
1988	17.857142857142858
1989	13.449367088607595
1990	11.217948717948719
1991	11.982881597717546
1992	10.606060606060606
1993	9.985096870342772
1994	14.904679376083187
1995	18.069815195071868
1996	13.636363636363635
1997	20.44334975369458
1998	31.420765027322407
1999	23.61111111111111
2000	29.383886255924168
2001	13.610149942329874
2002	3.5256410256410255
2003	2.832556471853711
2004	3.075103489059728
2005	2.807646356033453
2006	3.1453669594786056
2007	3.6551077788191186
2008	4.842259721203228
2009	3.362944162436548
2010	3.343653250773994
2011	2.339622641509434
2012	3.5908596300326447
2013	6.435911303407248
2014	5.669291338582677
2015	7.43801652892562