Year	kg per hectare
1961	650
1962	650
1963	650
1964	650
1965	485.7
1966	487.2
1967	488.9
1968	440
1969	437.5
1970	308
1971	303.3
1972	191.7
1973	238
1974	314.3
1975	444.4
1976	454.5
1977	375
1978	333.3
1979	428.6
1980	531.3
1981	428.6
1982	440
1983	385.7
1984	493.6
1985	400.9
1986	534.3
1987	607.2
1988	481.9
1989	273.8
1990	334.6
1991	252.9
1992	302.1
1993	359.1
1994	250.3
1995	262.9
1996	317.2
1997	146.9
1998	141.5
1999	1162
2000	794.8
2001	637.3
2002	148.5
2003	379.2
2004	385.2
2005	243.2
2006	218
2007	158.8
2008	233.8
2009	230.8
2010	220
2011	177.8
2012	196.2
2013	182.3
2014	34.3
2015	276.5
2016	178
2017	0.1
2018	22.7
2019	23.2
2020	15.7
2021	16.3
2022	11.5