Year	% of total
1960	14.1439205955335
1961	13.369565217391305
1962	11.144278606965175
1963	8.455565142364106
1964	7.899305555555555
1965	6.864988558352403
1966	5.464868701206529
1967	3.813559322033898
1968	2.718676122931442
1969	1.3232514177693762
1970	0.7420340462680053
1971	0.8406725380304245
1972	0.5924170616113744
1973	0.2366863905325444
1974	0.3090659340659341
1975	0.2329450915141431
1976	0.3224860744649663
1977	0.23189899510435455
1978	0.18621973929236496
1979	0.18467220683287164
1980	0.11003521126760561
1981	0.6082009024916618
1982	14.758980085613253
1983	31.844355260861974
1984	40.548080078766
1985	48.74123645634161
1986	50.51369863013699
1987	57.522697795071345
1988	63.79353233830847
1989	66.38472692121798