Year	kg per hectare
1961	1099.1
1962	1142.1
1963	1128
1964	913.9
1965	911.4
1966	1010.4
1967	1725.6
1968	1006
1969	1041.1
1970	1187
1971	1498.2
1972	1593.9
1973	1007.5
1974	1875.8
1975	1624.4
1976	1391.5
1977	1752
1978	1876.2
1979	1609.6
1980	2017.3
1981	2680.3
1982	1659.8
1983	960.2
1984	1083.9
1985	1575.9
1986	1589.4
1987	1628.7
1988	1671.5
1989	2281.9
1990	1877.3
1991	1986.1
1992	944.7
1993	2160.1
1994	2585
1995	1419.2
1996	2490.2
1997	2271.8
1998	2181.7
1999	2191.4
2000	2765.9
2001	2424.1
2002	2772.6
2003	2536.8
2004	2777.9
2005	3309.6
2006	3141
2007	2790.3
2008	4063.2
2009	4405.5
2010	4150.4
2011	4017
2012	4243.5
2013	4043
2014	4899.6
2015	3348.4
2016	3623.1
2017	5331.8
2018	4651.9
2019	4101.8
2020	5121.1
2021	5151.1
2022	4964