Year	kg per hectare
1961	814.4
1962	787.1
1963	792.1
1964	620.8
1965	760
1966	778.9
1967	844.3
1968	901.3
1969	688.4
1970	797.1
1971	665.4
1972	726.6
1973	664.5
1974	618.3
1975	758.2
1976	785.7
1977	701.5
1978	623.9
1979	637.8
1980	699.2
1981	795.2
1982	687.3
1983	675.7
1984	885.5
1985	1244.1
1986	1375.2
1987	1530
1988	1769.4
1989	1520.7
1990	1530.7
1991	1614.5
1992	1441.7
1993	1431.6
1994	1394.8
1995	1402.2
1996	1366.5
1997	1110.3
1998	1145
1999	1038.2
2000	1097
2001	1004.9
2002	1067.3
2003	1075.9
2004	1164
2005	1325.6
2006	1412.6
2007	1346.1
2008	1490.3
2009	1632.2
2010	1723.8
2011	1588.7
2012	1512.1
2013	1397.7
2014	1394.8
2015	1402.1
2016	1414.4
2017	1385.9
2018	1397.3
2019	1287.3
2020	1343.2
2021	1352.7
2022	1455.9