Year	kg per hectare
1961	1857.5
1962	2042.3
1963	2041.6
1964	2111.7
1965	2320.6
1966	2401.7
1967	2491.5
1968	2576.3
1969	2986
1970	2538.2
1971	3132
1972	3339.8
1973	3593.6
1974	3825.8
1975	3902.7
1976	3686.2
1977	4106.5
1978	4460.4
1979	4131.9
1980	4806.1
1981	4619.6
1982	5177.9
1983	4734.3
1984	5401.2
1985	5158.8
1986	4960.8
1987	4980.3
1988	5224.6
1989	5472.8
1990	4520.8
1991	5486.2
1992	3646
1993	3085.3
1994	3968.8
1995	4064.1
1996	3999.6
1997	4785.7
1998	4554.2
1999	4706.2
2000	3632.7
2001	4884.9
2002	3963.2
2003	3038.9
2004	5589.9
2005	5526.6
2006	5097.3
2007	3492
2008	5800.2
2009	4715.2
2010	4719
2011	5105.1
2012	3761.1
2013	4831.5
2014	5897
2015	5243.4
2016	6486.6
2017	5835.5
2018	6286.2
2019	6365.8
2020	6659.1
2021	5920
2022	4032.1