Year	% of total
1970	2.113234997158438
1971	2.1017023013378213
1972	1.780469692878917
1973	2.1125697870164184
1974	2.5529204617063463
1975	2.5909801363604417
1976	2.930628597255275
1977	2.4346090784538332
1978	3.0599254087201873
1979	3.683673110409201
1980	3.593132566772984
1981	2.9293178864821687
1982	3.50422423597608
1983	3.687366357698489
1984	3.6937187357837713
1985	3.582072613323724
1986	4.59270079450364
1987	4.068571531045835
1988	3.623440915494501
1989	3.791433382195634
1990	4.545454545454546
1991	4.3478260869565215
1992	4.3478260869565215
1993	4.3478260869565215
1994	4
1995	4
1996	3.8461538461538463
1997	3.8461538461538463
1998	7.4074074074074066
1999	7.142857142857142
2000	6.896551724137931
2001	9.090909090909092
2002	7.6923076923076925
2003	7.4074074074074066
2004	7.6923076923076925
2005	11.538461538461538
2006	12
2007	11.538461538461538
2008	12