Year	% of total
1971	22.093023255813954
1972	21.49532710280374
1973	22.115384615384613
1974	14.285714285714285
1975	14.772727272727273
1976	9.79020979020979
1977	11.464968152866243
1978	12.068965517241379
1979	11.917098445595855
1980	6.451612903225806
1981	3.9525691699604746
1982	1.5432098765432098
1983	0.8356545961002786
1984	1.0362694300518136
1985	0.6976744186046512
1986	0.18484288354898337
1987	1.0638297872340425
1988	3.767123287671233
1989	0.13966480446927373
1990	0.11389521640091116
1991	3.4334763948497855
1992	5.304740406320542
1993	6.645230439442658
1994	8.01980198019802
1995	3.0936454849498327
1996	3.276003276003276
1997	9.153122326775023
1998	9.520000000000001
1999	4.533152909336942
2000	1.62748643761302
2001	0.96411355115158
2002	0.18841262364578426
2003	0.17644464049404499
2004	0.5789909015715468
2005	0.6316620607974733
2006	0.4730713245997089
2007	0.3223495702005731
2008	0.3200568990042674
2009	0.4173354735152488
2010	0.09351620947630923
2011	0.057273768613974804
2012	0.5349099099099099
2013	0.2843332385555872
2014	0.02633658151171978
2015	0