Year	kg per hectare
1961	1746.6
1962	1822
1963	1858.6
1964	2137
1965	2297.1
1966	2930.6
1967	2951.4
1968	2439.4
1969	2822.4
1970	3124.1
1971	3184.4
1972	3702.2
1973	3492.9
1974	3184.2
1975	3430.5
1976	3741.8
1977	3381.4
1978	3498
1979	3791.6
1980	3705
1981	4062.1
1982	4669.5
1983	3717.2
1984	4497.9
1985	2915
1986	4047
1987	3694.7
1988	3705.5
1989	4402.1
1990	3953.7
1991	3990.8
1992	2953.6
1993	2512.7
1994	2798.9
1995	3069.5
1996	1908.6
1997	3011.5
1998	2684.7
1999	2946.8
2000	2459.9
2001	2898.5
2002	3156.3
2003	2371.3
2004	4077.8
2005	3387
2006	3572.5
2007	2523.7
2008	4094.3
2009	3413
2010	4031
2011	4251.2
2012	3671.8
2013	4561
2014	4860.7
2015	4669.6
2016	4817.8
2017	5479.7
2018	5561.7
2019	5774.7
2020	4373.4
2021	5949.6
2022	5151.2