Year	% of total
1970	3.005991793406386
1971	3.10029525614769
1972	3.1216496359416586
1973	2.850423918410736
1974	3.704806025659507
1975	3.4531048491491876
1976	3.318460236015856
1977	2.817788926346449
1978	3.33337407474205
1979	3.038551140299831
1980	2.429118900210074
1981	2.895953853804849
1982	2.525500199159528
1983	2.7427922534834437
1984	2.757908569757327
1985	3.033611169472198
1986	3.1084508886747653
1987	3.035313383671806
1988	3.3210223084898662
1989	3.094416621856211
1990	6.547619047619048
1991	6.321839080459771
1992	6.779661016949152
1993	6.666666666666667
1994	6.282722513089005
1995	7.027027027027027
1996	6.103286384976526
1997	5.829596412556054
1998	5.603448275862069
1999	5.701754385964912
2000	5.737704918032787
2001	6.965174129353234
2002	6.0344827586206895
2003	7.177033492822966
2004	7.5
2005	6.25
2006	7.76255707762557
2007	8.296943231441048
2008	10