Year	% of total
1970	6.717618590359688
1971	6.022014970305559
1972	5.553486681682142
1973	4.680183728575094
1974	5.049670725602134
1975	4.348129229726971
1976	4.616042830942011
1977	5.144719772298891
1978	4.445025001037431
1979	6.437090035219627
1980	6.445391892308844
1981	8.128800444199323
1982	8.68985673355187
1983	9.298147930616894
1984	9.0075237212914
1985	9.041248619650567
1986	9.21121098842614
1987	9.263819505534393
1988	8.426881542537823
1989	8.435538255451851
1990	4.721862871927555
1991	4.444444444444445
1992	3.9873417721518987
1993	3.8292529817953542
1994	3.508771929824561
1995	3.2479700187382887
1996	3.25
1997	2.9375
1998	2.8606208155812536
1999	2.487864077669903
2000	2.357100766057749
2001	2.346041055718475
2002	2.1828908554572273
2003	5.821917808219178
2004	2.0506634499396865
2005	2.111801242236025
2006	1.9925280199252802
2007	2.142857142857143
2008	2.1767810026385224