Year	kg per hectare
1961	1410.7
1962	1604.9
1963	1511.2
1964	1695.4
1965	1403.2
1966	1557
1967	1606.4
1968	1313.3
1969	1554.7
1970	1775.3
1971	1783.5
1972	1609.5
1973	2041.4
1974	2046.2
1975	1955.9
1976	1907.2
1977	2134.9
1978	2424.3
1979	2252.2
1980	1874.1
1981	2425
1982	2442.8
1983	2330.1
1984	2581.5
1985	2439.5
1986	2582.2
1987	2382.6
1988	2527.9
1989	2129.4
1990	2250.8
1991	2433.1
1992	2928.6
1993	3054.5
1994	2759.8
1995	2900.2
1996	2715.1
1997	3010.7
1998	3812
1999	3335.6
2000	3461.8
2001	3398.6
2002	3275.7
2003	3308.7
2004	3658.8
2005	4075.8
2006	3707.6
2007	4294
2008	4116.5
2009	3249.3
2010	4876.2
2011	4596.3
2012	4162.4
2013	4795.6
2014	4827.3
2015	4779.1
2016	5203.4
2017	5404.6
2018	4671.2
2019	5474.5
2020	5164.2
2021	5193
2022	5070