Year	kg per hectare
1961	1250
1962	1250
1963	1250
1964	1500
1965	1250
1966	1500
1967	1500
1968	961.5
1969	892.9
1970	840
1971	714.3
1972	750
1973	632.7
1974	700
1975	700
1976	700
1977	700
1978	700
1979	700