Year	% of total
1970	29.590916461013688
1971	31.302048342986044
1972	31.777554328359
1973	33.31265696296095
1974	29.70608509480503
1975	29.682614050316538
1976	26.694475487910687
1977	32.672563477167074
1978	26.695091516698614
1979	25.053458535547048
1980	24.87765920635391
1981	25.98958042444519
1982	23.93691784934236
1983	21.08711445689807
1984	18.879552204552667
1985	10.864133521569542
1986	8.858968950364881
1987	8.646585705545737
1988	8.414028315471608
1989	8.751729335259874
1990	6.25
1991	6.25
1992	11.76470588235294
1993	11.76470588235294
1994	11.76470588235294
1995	11.76470588235294
1996	11.76470588235294
1997	5.555555555555555
1998	5.555555555555555
1999	5.555555555555555
2000	5.555555555555555
2001	5.555555555555555
2002	10.526315789473683
2003	10.526315789473683
2004	9.523809523809524
2005	10
2006	10
2007	9.523809523809524
2008	9.523809523809524