Year	kg per hectare
1961	996.3
1962	1025.3
1963	1030.2
1964	1035.7
1965	1045.5
1966	1062.8
1967	1113.1
1968	1105.4
1969	1330.7
1970	1350.3
1971	1272.2
1972	1163.9
1973	1186
1974	1224.7
1975	1286.3
1976	1353.8
1977	1488.1
1978	1509.9
1979	1581.3
1980	1606.4
1981	1646.6
1982	1822.6
1983	1659.9
1984	1747.3
1985	1841
1986	1914.7
1987	1847.3
1988	1877.2
1989	1945.4
1990	2099.5
1991	2042.3
1992	2105.2
1993	2212.5
1994	2261
1995	2273.4
1996	2307.5
1997	2374.7
1998	2240.9
1999	2464.8
2000	2580.8
2001	2667.8
2002	2730.6
2003	2823.4
2004	2992.3
2005	3049
2006	3180.8
2007	3319.8
2008	3334.3
2009	3228.9
2010	3231.9
2011	3340.6
2012	3492.6
2013	3531.8
2014	3637.4
2015	3556.1
2016	3529
2017	3692.3
2018	3670.5
2019	3737.9
2020	3769.4
2021	3834.8
2022	3821.6