Year	kg per hectare
1961	596.4
1962	598.8
1963	694.8
1964	697.3
1965	742
1966	550.9
1967	1027.9
1968	1176.3
1969	1272.7
1970	1628.7
1971	1529.1
1972	1414.9
1973	1860.7
1974	1313.2
1975	1054.7
1976	1450.4
1977	1592.2
1978	1851.9
1979	1711.2
1980	1988.6
1981	2071.5
1982	2030.5
1983	1865.2
1984	1526
1985	1515.9
1986	1753
1987	1706.6
1988	1686.6
1989	1612.4
1990	2013.8
1991	2485.1
1992	2289.7
1993	2185.3
1994	1898.1
1995	1917.7
1996	2504.9
1997	2394.2
1998	2458.5
1999	2805.4
2000	2418.3
2001	3100
2002	2448.9
2003	2851.8
2004	2365.7
2005	2869.5
2006	2672.3
2007	2939.5
2008	2427.2
2009	2686.5
2010	3223.4
2011	3155.5
2012	3451.1
2013	3615.6
2014	3594.6
2015	2897.8
2016	3164.6
2017	4229.1
2018	4043.7
2019	2946.5
2020	3526.3
2021	4289.5
2022	4476.2