Year	% of total
1970	5.496335008627537
1971	5.561591183794474
1972	5.742618310288443
1973	5.602319330020608
1974	5.374993933243618
1975	5.527023175151821
1976	5.424880094602236
1977	4.722806188247263
1978	6.596095156932395
1979	5.848393966129721
1980	7.100311497370913
1981	6.907875016961827
1982	6.124740019878034
1983	6.364048331868324
1984	6.602687946726076
1985	6.001369250730902
1986	6.021164757139412
1987	5.961366089240086
1988	6.1318081759814484
1989	5.0618366519683455
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0