Year	% of total
1970	1.436591646140589
1971	1.3942790349473668
1972	1.2739522682185807
1973	1.6935442188571386
1974	1.6566673879597351
1975	1.5881956811258675
1976	1.4321716391224637
1977	0.5391889551876399
1978	0.9614520496634305
1979	0.8013377910163368
1980	1.4919323469195724
1981	1.3594648666960405
1982	1.388448233138777
1983	1.8470011726218594
1984	0.9885213680534615
1985	1.2151157202650724
1986	1.3532005433705376
1987	1.2921479756363996
1988	1.5552783685134073
1989	1.5950586487536291