Year	kg per hectare
1961	1108
1962	1160.1
1963	1056.5
1964	2044.4
1965	1852.8
1966	1052.7
1967	2060.8
1968	1481.3
1969	1348.4
1970	1186.3
1971	1791.6
1972	2642.5
1973	2278
1974	2353.8
1975	2179.7
1976	1790.8
1977	1911.2
1978	1530
1979	1249.7
1980	2316.6
1981	1954.7
1982	1669.5
1983	3261.2
1984	1638.9
1985	2240.5
1986	2460
1987	3566.7
1988	2846.6
1989	2776.5
1990	3486
1991	2644.1
1992	3266.9
1993	3014.9
1994	1885.6
1995	3133.7
1996	2797
1997	1969.2
1998	2470.1
1999	1668.4
2000	2443.3
2001	2454.8
2002	2689.5
2003	3306.5
2004	3066.7
2005	2951.9
2006	2398.5
2007	2752.1
2008	2438.8
2009	3174.1
2010	3037.6
2011	3669.3
2012	4299.5
2013	4177.1
2014	4910.1
2015	4978.9
2016	4834.9
2017	3196.9
2018	2461.7
2019	3624.2
2020	3834.1
2021	3353.4
2022	3201.2