Year	% of total
1971	7.142857142857142
1972	6.896551724137931
1973	8.240977550440466
1974	10.376134889753567
1975	10.260405074560428
1976	8.761213972132087
1977	8.89377749842866
1978	9.036375239310784
1979	10.177514792899409
1980	6.061670912764649
1981	5.640835953393749
1982	4.391100702576113
1983	3.707136237256719
1984	3.1347962382445136
1985	2.9085014065703527
1986	2.6921523758244716
1987	11.550422034651266
1988	11.087420042643924
1989	10.896898575020955
1990	10.833333333333334
1991	4.324843825084094
1992	2.766798418972332
1993	2.2813688212927756
1994	2
1995	1.9164173082742157
1996	1.8974068772677342
1997	1.9150268631134844
1998	1.9163031184359347
1999	1.916801317998923
2000	1.915360501567398
2001	1.9162196521038108
2002	1.5267400998139562
2003	1.5278757939308398
2004	1.526552097847964
2005	19.736842105263158
2006	18.02323862460456
2007	17.257875259499954
2008	9.447516807633919
2009	8.526435384574734
2010	9.746871677435184
2011	6.302061109771256
2012	9.54409144247903
2013	8.142480572387115
2014	4.325050171172235
2015	3.7317547372391977