Year	% of total
1970	11.415080102844952
1971	11.41140119625109
1972	12.044841961126474
1973	11.976909139764112
1974	11.881726514528602
1975	12.08001287562036
1976	11.184797809764607
1977	11.067059806026084
1978	10.357976248962595
1979	10.306918713815339
1980	10.310106290711198
1981	10.632069270068794
1982	10.871977667030047
1983	11.011043178927462
1984	11.085140675235241
1985	10.404596103168478
1986	10.462252002077339
1987	10.50417769003303
1988	10.175487145987917
1989	9.995583936564106
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